I've read through this thread from start to finish. My thoughts: What she does to her daughter (throwing her out in the middle of the night, and probably plenty of other instances of emotional/mental abuse) sounds exactly like what my mother used to do to me from the time I was 7 years old until child services was finally involved when I was 15. It creates an incredibly invalidating and insecure environment for the child, and I absolutely believe that authorities need to be involved. No one is protecting this child or giving her a consistent sense of security, and I can tell you from personal experience that will have an effect on her which will take years to undo if she can ever undo it.

I know we can't really diagnose someone based on second hand information (that, and we're not therapists), but she does sound like she has borderline personality disorder which is what my mom's diagnosis was. In which case, without any shred of therapy, this will not change. The cycle will just continue with you being on the losing end, regardless of how hard you try to make it different. I'm sorry to be blunt, but I feel for you and for her daughter.

A previous poster was upset that we were advocating for you to abandon someone with a mental illness. Well, when that person has no desire or plan to change, what course of action is there besides being dragged into the vortex with that person? When I was with my ex-fiance, his close friends encouraged him to leave me and I was incredibly upset. Now, over 10 years later, I get it and I don't blame them. There was no winning solution. We'd been through trying to make things work. I wasn't interested in change at that time. Sometimes people have to cut their losses, and take care of themselves rather than martyr themselves.