Don’t let her see your daughter either, if he mentions she’s coming to visit or he is going to visit her, you go out with your daughter and make plans for the day instead. Crossing boundaries is disrespectful and it only teaches your daughter that it’s ok to do, and definitely not a valuable or useful lesson for her to learn.
Similar! My MIL prior to my daughter used to try to set my partner up with her friend’s kids ect because she wanted him to live with in London and not me in Wales. She did other spiteful things and once found out I was pregnant tried to lick my ass but damage was already done by that point. Anything nice happens to us and she cries makes it about herself. How sad she is that she doesnt live close to us. She has two other children at home with her. Before our daughter was born we went to couples therapy and spoke a lot of her. She was a drunk and would take her anger out on my partner when he was growing up. If he ever spoke to her about anything it was always end up her victim and be argumentative towards him. So he was afraid to say anything to her and still is! He has no boundaries with her at all so I set them and look like a bitch but idc what she thinks of me and I dont see her often! You’ll just have to make sure you dont see her much!
If he’s aware of her behaviour, just let him deal with her. You can go no contact with her and he can stay in the abusive relationship he has with his mother if that’s what he really wants. But ngl if he isn’t standing up for you, he isn’t a good partner and you deserve someone that can and would do that for you.