This sounds like a toxic relationship. Give her good advice once and for all... if she doesn't follow up on any of it, then you have to end the relationship in your own best interest. (There are places she can get help, even help to get out of her situation.) At the very least she needs a professional as a T, not a friend.

If you don't feel you can do this, for yourself, then you must put parameters on the friendship... she can only call during such and such hours, any threatening of ending it (rather than leaving the relationship) will garner a call by you to her local police... etc. Maybe once she finds out you won't just listen to her moaning, she'll quit calling.

You have to take care of yourself. If you are unable to end this, for now at least, consider therapy for yourself for enabling behavior. Take care of you first!