my mother is was too friendly with my ex!

So I made a post about this a year or so ago but I need to make another (cause apprenlty people don't change!) Here's a bit of back story first: I met this guy in September 2016, we were friends for a while, he seemed really lovely and sweet so in March we went on a date. Pretty much straight away things went tits up and there were red flags popping up all the time, he would constantly go on about women he wants to fuck, then acuse me of cheating on him, we'd 'playfight' and he'd often take it too far, he'd bruise me and choke me, he'd constantly tell me Im fat (despite the fact I'm 9 stone and he's 25...) I'm ugly, stupid, worthless all that lovely stuff! so after nearly 3 motnhs I called it quits. well here's the thing, my mum and him have always been way too close, he called her 'mum' she called him 'son' and when we broke up, she called me a bitch and said I should've given it a chance! well it's been over a year since we broke up, I've been with my current bf for nearly a year (who is an absolute angel, but surprise my mum hates him!) . and here's the thing, my mum STILL refers to my ex as son, they still talk and want to meet up, and she said recently that she'd invite him to my sister's christing if I wasn't with my boyfriend!! and it pissed me off SO MUCH! for a start, he's SEVENTEEN and she's THIRTY FOUR! that's a little creepy to be friends? and the fact I've explained to her again and again he is NOT nice person (when we broke up he spread a load of lies but that's another story!) and not to trust him but noooope still kissing his ass!! and she begrudgingly said okay to my current bf coming along to the christening. Oh and she refers to my ex as my sister's big brother but I got told off when I jokingly called my bf that?! I just... don't understand why she is friends with him and why she hates my current bf and for the love of God can someone please tell me I'm in the right for being angry?! I don't really know what to do but it's driving me up the wall cause she's constantly trying to break me and my bf apart so I can 'get someone better' but she thinks my someone better treats me like shit?? she also patronises me about abusive relationships, telling me all the signs and what to do and I'm like yes I ended one before it spiraled into abusive but you want me to get back together with him! I just needed to vent and have a second opinion 😦 thanks for reading my long rant!!!