Suffering...unite? ...Ok, whatever.
Yeah, he pretty much had turned his life around from being a teenage druggie, to a responsible, loving husband and father and grandfather. He was certain his best friend would have done the same. However, his friend's father was so mortified about having a drug-addict son, that he shot him square in the chest while the friend was high on barbiturates. The movie goes with the father's story, which is that he shot his son in self-defense, but too many things don't add up.
I'm sorry- but I agree with most people's opinion- you don't do something like that to your kid no matter what. I can understand why the guy(known in the movie as "Brick") lived with his friend's death as he did.
Well, at least Brick doesn't have to carry the "What if...?" burden anymore.