Ultimately if there is no reason to change then she most likely won't. It's hard but yes, you need to set some serious boundaries. Maybe tell her "We(I) want to see you get better and whatever we(I) have been doing isn't working. If you are still hurting get help from someone that can help you. I love you and want you to be happy and you aren't right now. I want to be friends but your hurt is more then I can help you with. Please call someone better equipped to make you happy." Then you have to do what the others above said. I am sorry you are put in a place where you have to do this.