Transcript for Hollywood exec's mysterious illness that led to a hand transplant: Part 1
Tonight you're about to meet a hard-charging Hollywood executive whose life came to a screeching halt a mysterious illness bringing him to the brink of death. But his condition and his determination made him the perfect candidate for a ground-breaking human hand transplant. His dogged fight back captured in emotionally raw home videos should viewers might find disturbing. But his triumph unflinching. This is one of the most exciting things that could happen. Ready? Okay, ready. High five. Okay. Reporter: For Jonathan little moments like this are within reach. There's nothing more independent than being able to drive around by yourself. Reporter: For the first time in 2 1/2 years, this father is behind the wheel of his own car. On the open road. I've felt the breeze before but right now it feels electrified. Like it's humming on the inside. So I think that means that nerves are growing back. That's amazing. Your hand is humming on the inside. Reporter: His new hand coming to life. Because two years ago, the hand he was born with looked like this. Categorize this as not good. Reporter: The successful Hollywood executive defied unthinkable odds. After a two-year medical odyssey that left him narrowly escaping death and getting a new left hand in a remarkable feat of science. With his girlfriend of seven years at his side, Jennifer Gunkel documenting her own raw emotions. He's saved my life so far. Reporter: And watching his determination to heal. That's awesome. Reporter: But then he was a 49-year-old entertainment executive. At the top of his game. Hanging with jewel, publicizing their movie "Ring of fire." He was also behind the miniseries "The kennedys" starring Katie Holmes. Today's a big day. Your daddy's going to become president. Reporter: Jonathan was on his way to a reality television conference in D.C. When he was suddenly slammed with what seemed like the flu. Felt like I had been hit by a truck. And I said, can you please help me get cleaned up? Get me out of here somehow? You were going to power through? Power through. It was a very important trip for my team and they'd been preparing for a long time, I needed to be there. Reporter: He drove to the E.R. Where he got a shot of morphine before dragging himself onto a cross country flight. He arrived in D.C. But within 24 hours, he was fighting for his life. In icu at George Washington university hospital. It was an unthinkable plot twist for a movie producer who never drank, never smoked, and exercised like a fiend. Now doctors telling him to text everyone he loves, believing he has only hours to live. I made a very conscious decision with the last moment of consciousness I had not to text my daughter. Because when they told me that I had a small chance of living, that moment when I decided not to was really the moment that I decided that I just can't die. I can't. I can't do it. She shouldn't grow up without her daddy. Reporter: Doctors had no idea what was killing him but they did know his body was falling into septic shock. He was put into a medically induced coma. Wish I could have talked to him. I am just -- I wish I would have gone sooner. Reporter: Jennifer rushing to his bedside. They're testing for everything, everything's come back negative. Reporter: His odds of surviving just 10%. It was described to me as multiple organ failure. His lungs, his heart, kidneys, he had to have dialysis, everything was shutting down. Reporter: Jennifer had been entrusted to make life or death decisions for the divorced, devoted dad. The kind who'd never miss a father-daughter dance. I kept thinking about his daughter. It was just like she -- she can't be without her dad. So I was thinking every moment, every decision I made was like, this little girl. Essentially, you held his life in your hands. I know. And that was a really scary thing for me. Reporter: During his coma, hovering between life and death, Jonathan says he experienced powerful nightmares. One presented him with a critical choice. A voice, a very deep, very distinct, male voice, I don't know if it was my own consciousness, if it was a doctor by my bedside, if it was god, I really don't know even to this day. And it said, if you do decide you want to live, it's going to be in the most vicious, painful, awful fight every day for the rest of your life. And you were up for the fight? Well, yeah. When you put it that way it was like, that I get. So I said yes. Reporter: The instinct to fight, something instilled in him as a young boy. Mesmerized by the movie about a tenacious boxer, an underdog named rocky. My dad took me to a drive-in movie when I was 11 years old and we saw "Rocky." From that moment forward I just knew it was inside of me way more than I had ever thought before that day. You took "Rocky" as gospel. It is the gospel. First of all, he didn't win. Rocky didn't win. People don't really think about that. It's about doing the work. It's about putting everything you have into it. If you just literally do your best at everything, that's really awe you can do. Reporter: After his near-death experience he woke with a newfound appreciation for what was important in his life. Do you have a conscious memory of seeing Jennifer the first time you came out of the coma? I wanted to marry her. That's the truth. We were not married and probably planning on not being married. Reporter: The coma lasted 2 1/2 weeks. The damage, severe. His body had shut off oxygen to his outer limbs to preserve his organs. His hands and feet were starting to die. Necrosis and gangrene setting in. What does the pain feel like in your hands? It feels like somebody's holding a bic lighter underneath my fingertips all day, every day. Reporter: Doctors wanted to amputate but Jennifer intervened. When they came and said, we want to amputate, I immediately said, absolutely not. Reporter: She began searching for other options. And eventually stumbled upon the possibility of a hand transplant. Turns out UCLA boasts pioneering hand transplant research. Only 85 have ever been attempted globally. And a world-renowned hand surgeon, Dr. Cody azari, had been scouring the world for his next patient. I was looking for someone that was motivated, that was healthy, and had not had his amputations done. Reporter: Because Jennifer had made the critical decision not to have Jonathan's hand amputated, he became the perfect candidate for Dr. Azari. Why go through all these surgeries? Why not just go with a process thet Nick. When you of that transplantation they oftentimes put you through psychiatric exercises. One of the questions is why do you want another hand? And I thought, well -- I mean, you have two. You know? I think the world's built for two. And I can handle it. Reporter: Dr. Azari and his team began the process by amputating Jonathan's left hand, preserving his nerves and blood vessels for the eventual transplant. But Dr. Azari also told him to get stronger and healthier. He was also gauging something else. What did you size up about his mental toughness? His mental toughness was what actually got me to fall in love with his personality. He is an eternal optimist like I've never seen before. Reporter: But the eternal optimist faced a grim reality, that his right leg could not be saved. That was an extraordinarily painful moment. She was crying with me. It was a real get it out cry. The admission that we have lost that battle was really tough for both of us. Reporter: He may have been missing a leg, a hand, all of his fingers and toes. But just like his movie hero rocky, even in defeat -- Come on, push it. Reporter: Jonathan kept fighting in order to qualify for that hand transplant. The first milestone? Oh my god. Reporter: Learning to walk with his new prosthetic. There you go. What was that like, that moment, what went through your mind as he took those first steps? Don't want to fall. Jennifer was crying. I could see Scott in the mirror. I was walking towards him, I could see a big smile on his face. It was a heart-warming, chilling, just -- almost incomprehensible. That's about as big a rocky Balboa moment as you'd get. Reporter: Within months he'd have an even bigger moment. Running. Just like his hero. Finally, Jonathan was ready for that hand transplant. Buttal the way they wanted to make good on one particular promise. What was your wedding day like? Our wedding day was very sweet. It was really noneventful, which is the way we wanted it to be. Gas really a 30-second ceremony, it was joyous and happy. We really didn't want anything to change. After we got married, we got something to eat like we always do. Reporter: Their honeymoon period involved waiting for the ideal donor. You need to match for size, you need to match for color, you need to match for hair pattern. Reporter: It took seven months to get the call. How are you feeling about your hand transplant surgery? Very peaceful. And hopeful that everything goes well. Reporter: And then the complex surgery. 24 attendants. Countless nerve endings, veins, tries. Microscopically stitched together. Hand transplants are marathon surgeries because there's so many structures that need to be repaired. Nerves are like coaxial cables. Except there's no red to red, green to green, yellow to yellow connection. You have to figure out how they fit within each other so that the parts of the nerve that are for sensation match up and the parts of the nerve that are for motor function match up. Initial fears are that the vessels are going to clot and blood is not going to move through the hand. There's no margin for error? There's no margin for error. Reporter: Even if the surgery is a success, will he be able to control his new hand? Or touch or feel again when we come back.
This transcript has been automatically generated and may not be 100% accurate.