I think she needs to feel help, help that you can't give her. I'm not sure if she'll ever be able to have a health relationship with you or anyone but she needs to be the one who realizes she need to find help.

I'm sorry but the only thing I can relate to is the neediness that is deep rooted in this. I once had a friend who needed me in a way but at the end they ended up pushing me out of her life. The neediness end in them blaming me for their life problems in around about way. I still worry about that person but never want to speak or hear from them again.