My partner and I are having a very small, secret wedding December 2020. Originally, we had invited his mother (neither of us like her that much, but we felt she should be there, especially considering he is her oldest child), but they have been fighting a lot. We had hoped that things would get better before it came to this, but she pitched a fit over bringing him his birth certificate for an unrelated matter, insulted him and me, and claimed that everything was his fault. That was our last straw. We had invited her to a family vacation the week of the wedding (it was what we told both mothers, to keep them from trying to invite a million people we don't know or care about), and were planning to tell her it was the wedding closer to the trip. That night, we told her that, due to all of the fights, she would no longer be welcome (there were a lot more words, but that's the gist of it).
A bit more backstory: the woman absolutely despises me for reasons I don't fully comprehend other than she cannot control me. She constantly insults me, but never to my face, blames me for her son getting on antidepressants, and says it's my fault he is 'so disrespectful' (ie, stands up for himself).
He does not want to file a restraining order, because he still wants to see his siblings. We've told our wedding coordinator, but is there anything else we can do to keep her away?