As a non-parent, I make it a policy never to comment on parenting techniques or styles. I don't say "Parents should do this, shouldn't do that,", etc., even if some chick is beating her kids half to death with her sandal in the aisle of Wal-Mart (which does, indeed, happen about every third time I go to get hamster food, BTW). I just accept that some people take well to parenting (like my own parents) and find a style that is both successful and socially acceptable , and others, well... don't.
But I'm going to give some advice now to parents of grown children, children they've already (hopefully) raised.
Wait for it.
Kick your sons the hell out of the house before they're 20.
Kimveer Gill is the result if you don't do this one simple thing.
He was 25 years old, but reading his online musings you would guess that he was 18, tops. He had the life and mind of a child. A really disturbed, really lonely, child.