I'm so sorry you're having problems. He sure sounds like he's TOTALLY unsure of anything regarding his feelings. Any little thing makes him change his mind!
It's ridiculous that sliding the van down an icy hill would make him change his feelings for you. I know he has problems, but damage to a van is certainly NO reason to hold this against you!
I think I'd sit down and tell him that the fact that he's resenting you for the van is hurting you alot -- and you wish he could forgive you for it. That you didn't do it on purpose and you wish he'd just let it go!! Tell him your feelings for him, etc.
Like I said, I realize he has problems, and he really needs therapy badly! It would be good if you could talk him into going, but somehow I doubt you could do that from what you say about him.
I wish I could offer more advice. But I'm not sure I'd want to live like this. God bless and please take care. Hugs, Lee