I have a friend with a mother like that. She went through a period of self-harming and anorexia. Nobody could quite work out why such a nice, pretty, smart girl would do that, until they met her mother.
This is a woman who told her blue, shivering, skeletal, anorexic daughter (in my hearing) that she shouldn’t eat pizza because she was fat enough already.
Other lovely sentiments expressed by this hateful woman:
That my friend was too fat to wear the outfit she had chosen. That would have been difficult, becaused she weighed about 90lbs.
That there was no point applying to her chosen university, because she wouldn’t get in, and anyway, they weren’t going to financially support her unless she did accountancy.
That they weren’t going to pay for her ticket to our Formal (prom) unless she had a guy to go with.
But that no man would ever ask her, because she was fat and ugly and stupid.
When she did get a date, he wasn’t rich enough, smart enough or pretty enough to make them happy.
Thank goodness my friend came out, got a girlfriend, put on weight and doesn’t see either of her parents any more. She’s surprisingly well-adjusted, all things considered.
If your friend can’t physically cut her mother out of her life, she needs to get to a point where nothing that her mother says gets through. It’ll take a lot of work.