I have two D's (19 and 16) the oldest is not one to talk about it. I've used what I refer to as "backdoors" to get to some of their thinking with both D's.
The game is a boardgame that helps with communication and getting to know more about people. It has questions like: What would you do if you had a magic wand?; What do you daydream about?; what do you dislike most about yourself?; What does a happy family look like?
There is also a teen version that has two decks of cards (questions). One is lighthearted and the other more serious stuff like: What would you do if a friend started using dangerous drugs?
It's another tool for talking about different topics. You can probably get more info if you Google it.
Your son that "hates" his Mom, is a tough one. I think I got the brunt of the anger etc directed at me b/c D's live with me 24/7 and I'm the "safe" one. Doesn't make it any easier to handle though. It took alot of trial and error for me to be able to help my D's while at the same time "staying out" of their R with their Dad.
