Courtesy Michele Reiner
"I was never angry," says Reiner in his West Hollywood office, talking frankly about discovering that his son had used drugs just shy of his 15th birthday. " I felt bad for him and I didn't know what to do to help – and a lot of times parents don't know what to do."
What Reiner and his wife, Michele, did was ship Nick off to rehab. It was the first of what would become 18 stays in recovery facilities, eventually resulting in Nick becoming homeless when he refused to re-enter recovery at 19.
Photographed by Robert Maxwell
"You kind of throw yourself at the mercy of a lot of people who are supposed experts," says Reiner. "They'll all tell you these things, but they don't take into account your child. And you should know your child better than they do anyway. That is something I learned as we went along."
Nick explains that what saved him wasn't the facilities or the programs, but growing up and coming to terms with his experience. "I was able to wait it out long enough in order to see just a glimpse of things differently. That's all it took, just to see the situation I was in from a slightly different angle, says Nick. "Then the concept of life became clear to me."
For more on the Reiners' family struggle, pick up the latest issue of PEOPLE, on newsstands Friday
He started writing Being Charlie with a friend from his last rehab facility, Matt Elisofon, an experience that changed his life. "It was the first time in my life that I tasted life," says Nick. "Not everybody gets to make a movie. But in this case, I found my salvation."
And Reiner found his son again. Making the movie, he says, "forced us to look at what each other was going through. Anytime you get an insight into what somebody else is experiencing, it makes you understand them more. And if it's a father-son, a child and a parent, it makes the relationship better. Our relationship is better now than it was, and it's got places to go."
Being Charlie opens May 6.