David says he used to think that being a father to Nic would be enough to save his son. "Thomas Lynch wrote, 'If we can't protect our children, what good are fathers?' And that's the way I felt." Ultimately, David found that it was not his decision. In Beautiful Boy, David writes, "Your children live or die without you. No matter what we do, no matter how we agonize or obsess, we cannot choose for our children whether they live or die. It's a devastating realization, but liberating."

Nic chose to live and says he's found purpose in life. "I feel that's my mission every day to be honest and open and vulnerable and raw," he says. In Tweak, Nic writes on the last page, "My secrets will kill me if I don't get honest about my life. I can't have recovery, so my challenge is to be authentic."

Can you stop children from using drugs? Watch as Nic offers advice to parents. Watch