jess, those aren't easy questions to answer about his recovery in t. t has done wonders for me, but it also depends on what may be going on with him and how easy it is to treat. i have to say, wow, if he's in therapy and did it willingly at 18...that says alot about his desire to do well in life and with others.
i would be there for her as i have been in the past ONLY if it weren't hurting me. i would move on romantically and wouldn't consider a relationship with her for at least six months after they've broken up...if that happens. six months would show that they're probably broken up for good, and you wouldn't want her on the "rebound". i could be wrong. i'm older and it may just be age talking here.
i think you're a wonderful person to be there for her when she hurts. however you have to protect yourself emotionally too. i wish you so well on this one...it's a toughie.
kd