Family Communication Issues TW: Bullying

So, my mom refuses to let me say anything around my brother. When she isn't around we get along fine, we watch anime, or old Vincent Price movies, pizza parties you name it. But somehow every time I say something to him and she is around she turns it into a fight. She get's agressive and says things like "You need to buy yourself a muzzle." etc. (to me) and when she get's aggressively overprotective, he feels insecure and then starts shouting at me too and I get blamed for starting a fight. It doesn't matter if he accidently knocks over a chair and I tell him it wasn't his fault but a heavy purse that was on the back that knocked it over. Instant fight. Every single time. It's geting old and I don't know to get her to stop or if I can.

So, I thought I'd just vent this here, in my frustration. I generally don't take these things to heart because my family has been under a lot of stress lately, my sister just went through back surgery. But there's a point where verbalized personal attacks start to knock chinks in your emotional armour so to speak.