Sounds like a case of borderline personality to me. An ultimatum of some sort after her next eff up might be a good idea. She needs some tough love, let her know what her kids think and what you think. You could even include the kids in conversation, sort of like a small intervention. If you watch that show take some of their ideas.

You can even do the leg work, but do it in front of her. Make the phone calls and let them know you are calling on her behalf if she won't do it herself. Go with her to appts for your own peace of mind cuz she more than likely will play the victim and omit some crucial stuff. Best of luck