Here is what I would do:
Go meet her, but not as a child and mother. Think of her as a relative or friend if you can. You know by now that you will be an emotional wreck if you get your hopes up and she fails you again. Mental illness can be excused but that does not take away the pain. I hope you meet with her and come away being happy about it and not regretful.

(And I think you used the word "hell" in the right context. )