On Feb. 12 in Manhattan, Bon Jovi kicked off the Stand Up for a Cure concert series to raise money for lung cancer research at Memorial Sloan-Kettering, where guitarist Richie Sambora's father, Adam, spent his final days. With his mom, Joan, at his side, Sambora, 48, dedicated the show to his dad. He spoke to PEOPLE's Diane Herbst about one of the hardest times of his life.

What is your wish for the charity?
When you get that call that someone has cancer, you feel like you are drowning in a sea of disaster. The only thing you can possibly do is have hope. We hope we can spread information.

Were you with your dad at the end?
I was backstage [in Nashville last April] and my mother [called to say], "You better get here [to New York City]. We don't think he's gonna make it through the night." Jon said, "Take the jet and go." He held on for five more days.

You've said that you hit bottom.
I got divorced [from Heather Locklear and later split from Denise Richards]. I was going through a custody battle. I was having alcohol addiction problems, and my dad was dying and I was on tour and writing a record. I was emotionally busy. I was trying to slow down the speed of life drastically, but it was not working. It was a gang tackle from hell. And crawling out of that wreckage was a triumphant victory. My mom, the band, all my friends were very much supportive.

What's the toughest thing since you got sober [at Cirque Lodge last year]?
I haven't had any problems, thank God. Things are just getting better. Doing stuff like this [fund-raiser], being with my daughter [Ava, 10] and taking care of my mom. I love being a dad.

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