Break up blues from toxic parent

I’m really struggling with breaking up with my mum and her toxic attitude.

So I came out to her 2 yrs ago as a survivor of child abuse. She struggled to accept what had happened to me because I was raped by my older brother who she has a close relationship with. It’s hard enough dealing with it as it is. She maintains contact with him even now and is upset with me because I didn’t tell her sooner.

It’s 20 years later and then he got away with everything including battering me about whenever I did something he didn’t like. She was never around and never defended me always assuming the worst of me and dolling out beatings/punishments always taking his side of the argument because he was older. Would you feel able to say anything?

Anyway I ran off with my dad when they split about 3months after it happened. That was a brand new kind of nightmare as he was an alcoholic. Managed to get good grades in school but nothing special so went back to my mum when I was nearly 18 intending to join military to get the hell away from everyone. The reception was frosty along the lines of you made a mistake leaving to live with your father. Etc. Managed to get out and joined military I was living my life on autopilot for years until I was 23 and met my hubby. Pretending to be happy at weddings etc.

Now my life is alot happier or would be if I didn’t have to acknowledge my mum. She’s becoming more and more bitter and selfish as she gets older and has attempted to hit my daughter so that’s a red flag for me. I’m not heartless but she’s clearly choosing him again like she’s always done and still expects contact with my daughter. I dunno what to do. Im completely heartbroken. I didn’t ask for any of this how can my my mum treat me so shitty?