Because his son was a drug addled piece of crap who broke the rules and took a swing at a boss's kid. I never said that Dom was in love with the kid. He was an embarrassment LONG before that particular incident. But in my opinion there's no way he gave the okay.

And from what I've heard, the guy hasn't been the same since Nicky disappeared. It rattled that family to the core. The mother, the sister, these are decent people, in spite of what Dom is (and I'm not at all sugar coating that, the guy's a stone fucking gangster). What I'm trying to say is, maybe the guy is guilty of not going out of his way to protect his son. But he NEVER would have deliberately done it to his wife and daughter. Never.