My first take...guilt about his kids who don't live with him. Not having the kind of relationship with them where he feels he can be a disciplinarian. Loyalty, possibly too. All those things parents feel, especially the non-custodial parent. Add alcoholism on top of that, and you have a person who probably doesn't have a lot of coping skills to begin with. And anger and resentment...not a pleasant mix. I am sorry for your chaos.
How are you and your kids doing with this?