"He has got such an unbelievable attitude," Mills' father-in-law, Craig Buck, said. "He takes time out of his week each week to go up to the fourth floor of Walter Reed. That's where the most critically wounded guys that are coming back home are, and he'll put on all of his prosthetics and go visit them to encourage them."
Buck, 49, has spent the past six weeks at Walter Reed with Mills and his family and has been amazed by his resilience.
"Just his spirit, he lifts everyone up around him even though he's had such devastating injuries," Buck said. "Of course there's down times, which is to be expected, where he's not feeling so chipper, but 90 percent of the time he's positive, motivated and just works so hard at getting better."
Mills has prosthetics for both legs and both arms. He uses a wheelchair sometimes, but is already walking on his prosthetics. He hopes to be completely out of the wheelchair by November, using it only occasionally.
"It would be ways if I wanted to get down, but it wouldn't make my marriage very good and it wouldn't make my daughter very happy," Mills said. "She's one of the happiest kids I've ever seen and my marriage has never been stronger."
Mills calls his wife "a real hero" for helping him and staying by his side. He says his wedding band is his most prized possession. His brother-in-law pulled it off of his mangled finger after the explosion and Mills marvels that it does not even have a scratch on it. He wears it around his neck.
He is confident that his military career is far from over. His goal of being in the military for 20 years is unchanged after his accident. He hopes to be an instructor.
"I still have plans to stay in the military, if they'll have me," he said. "If I can give anything to the war effort, to the soldiers, to the guys that are signing up, I'm definitely willing to do it and I would love to."
He'll get a chance to address his thousands of fans and thank them tonight for their support. His only concern is he hopes he'll be able to get to everyone.
"I've never stopped wanting to help and I'll never stop training, teaching and pushing guys through what they need to push through," he said. "I'll give inspiration and motivation to anyone because that's my purpose. I don't take life for granted and I'm thankful I get to see my kid grow up and teach her to ride a bike."