Monster in law is a living nightmare

Boyfriends mom is a fucking nightmare.
First red flag was when we went to the cinema, boyfriend put his phone on DND, she rings him after screaming at him to pack his bags and move out.
Second red flag was the night I stopped boyfriend committing suicide, his 11 year old sister decided to start screaming at the top of her lungs and would not leave us alone. I told his sister she gave me a headache and she laughed in my face. His sister then read the private text conversation between me and boyfriend about her being a twat and told his mom. She loves bringing that up every time we argue.
Things were okay between us all before Christmas time, my mom even met his mom. I thought things had resolved. Around comes January, and I start questioning why I’m no longer allowed to sleep at his mom’s. Turns out I’m not welcome because I suffer from night time incontinence and she “can’t deal with that in her home” this argument leads to boyfriend having a massive panic attack which of course she blamed me for. I stopped talking to her then. In march I contacted her on boyfriends sisters birthday for reasons I won’t disclose here and practically got told to fuck off. In March/April boyfriend moves in with me and my mom and she wasn’t happy with that, even though he virtually lived here anyway. I didn’t even get a card on my birthday this year. So I’m like fair enough, she clearly fucking hates me. So I try to move on and forget her, then today as soon as me and boyfriend are sitting down to eat dinner she’s rang him up asking when his car insurance goes out which is normal fair enough. Then rings him back minutes later accusing him of being rude, saying boyfriend doesn’t want a relationship with her or his sister, questioning if he’s happy living with me “because he sounds sad on the phone” and hassling him about looking for work?! Boyfriend told her he’s had five job interviews in the last few weeks and she says yeah but you need to start looking properly.