Transcript for Celine Dion on Losing Husband, Brother to Cancer
She's known for hitting all the right notes on the world's most romantic songs, and tonight she pulls the curtain back on the emotional final moments with her husband who was her guiding light until the very end. ABC with the one on one conversation. Last time I took that step with you, we were three. I know. How are you? Very well. How are you? Good. I'm good. Reporter: It was last spring when Celine Dion and I stepped on this stage along with her beloved Rene. Then she was focussed on her husband who was in the retched throws of his cancer battle. He has a feeding tube. I have to feed him two times a day. Reporter: You did so much of this yourself. I do this myself. Reporter: Together they were preparing for the end. Which came just four months ago, two days shy of Rene's 74th birthday. When I saw you last time you were bracing yourself. You were beginning to talk about the end. Did it still come as a shock? Even when you're expecting it, you kind of -- I think I was more in shock when I did talk to you the last time. Because I saw him suffer. And that is the worst. Today, for me, it's like I don't live with him physically, but I live with him inside of me. Reporter: Her husband of 21 years slipped away quietly in the early morning hours of January 14th. I went there, and I stayed by his side. And then I started to talk to him. I started to talk to him and I said, you know what? I want you to just go in peace. I want you to not worry. You were worrying for my career. You were worrying for the children. You were worrying for everything. I promise you, we're going to be okay. Reporter: It was the moment they both knew was coming. He wanted to die in my arms. Reporter: Did he? I cannot live with a regret, but this is something that I do have a tendency to think that I have a regret and I should not. He did not die in my arms. But I think he died in my heart. If I hold onto this, I won't move on. There's a reason for things. I have to give myself a reason to go on. Reporter: Go on without the love of her life. âª âª you were my strength when I was weak âª Reporter: He was by her side as manager, then husband. The inspiration behind those unforgettable classics. âª Because I'm your lady âª âª and you are my man âª Reporter: Songs now taking on a whole new meaning. âª All by myself âª Reporter: Thousands attended the funeral in Mont recall, a public affair planned by Rene himself. You left me now with enough good memories of you to share with my younger brothers. Reporter: The couple's son, 15-year-old, offering a good-bye. As they grow older without you being around, I'll make sure to pass on what I've learned from you. Reporter: His mother's grieving only beginning. You've had a lot of loss. Not only your husband but your brother two days later. Yes. Reporter: Do you ever find yourself saying how much can I take? My brother who passed away of pretty much the same cancer as him died on Rene's birthday, and I said to myself, for his birthday my husband came and got my brother. Because my brother was too weak to fly on his own. Reporter: One last parting gift. For Rene's birthday, he said I'm going to come and get your brother and take good care of him. Reporter: What do you miss most at this moment? What's the hardest part going forward without Rene? What's hard, I have to say, that when I have to take decisions now. Reporter: Do you ever say what would Rene do? I think we all do. Do you think Rene would think this song is appropriate? But after a while am I going to have signs all the time? Or do I have to make decisions as a woman, as a mother, as an artist? Reporter: Are you ready for that? Do I have a choice? You're never ready for something like this to happen. Even though you expect it, when it hits you, you're not prepared. It's hard. Reporter: Her first difficult decision, how to break the news to her three boys. Including five-year-old twins, Nelson and Eddie. I said, do you remember the movie "Up"? They said yes, she went up with the balloons. I said, well, yeah. I said, you know, today papa went up. So long boys. I'll send you a postcard from paradise falls. The only thing I want you to remember is "Up". Up is a good thing. Don't worry. The house is not going to go with balloons in the sky. We still live in it, but papa went with balloons. Papa went up. Reporter: Only weeks later, the shattered singer back on stage honoring a dying wish. Reporter: Did you ever consider not coming back to the stage? Was that a possibility for you, maybe taking time? I never did. He wanted me to come back. Even while he was sick, he said I don't mind if you want to do your living will with me. But I want you to come back. I was his favorite singer. He believed in me so much. Reporter: And so did her fans. On the night of her return, a heart breaking moment as she sang all by myself. âª the words more poignant than ever. âª It's not to come back on stage that was difficult. It's when the curtain was opened and I could feel the energy, the sadness, and it's what I felt from them that made me tear, but it's what helped me too. I had to grieve. I had to do it. âª Reporter: Today that same theater host to record breaking shows -- âª -- now a treasure-trove of memories. I know you used to do a signal. I still do it every night. Reporter: At the center of the room, Rene's old seat. He would be over here watching the whole show. Reporter: Is there any one song now that when you sing it, it's all about you and Rene? When I sing the show must go on, because when he was sick, he always said, the show must go on. He gave me a lot of strength. He did. He did, and you know what? I'm at peace. Reporter: Somehow a peace that allows Celine Dion to go on. I'm happy he's not suffering anymore. It's a long road, but like I said, there's a lot ahead of me, but if I think too far ahead of me, I might be scared. I might ask myself too much questions. I just want to be here now. âª âª the show must go on âª Reporter: For "Nightline" in Nevada. Thank you. Celine Dion will perform this Sunday on ABC at the billboard awards.
This transcript has been automatically generated and may not be 100% accurate.