I would say that you should apologize for what you feel you shouldn't have done or said, and make your connection with him better, you are not responsible for keeping your parents together or their relationship with him... If I were in your shoes I would ask him to look for help to get to be independent, definitely don't convince your parents to divorce, nobody in your family needs that on top of what already is... But also ask him what he whats to happen.... It's his life... That, and remember you were a child, so don't go too hard on yourself... But yes, humans are more than capable of evil... And enjoying it too... :/ We didn't become top of the food chain because we were nice to nature and animals...