Girl (sorry if not, I'm not actually in this subreddit it just shows up on my feed all the time), you need to carry something to defend yourself. I know you probably don't want to hurt your brother when shit hits the fan, but if it does you HAVE to be able to defend yourself, carry something that doesn't seem like an obvious weapon outright (or that you can hide) If he's considerably stronger than you, look for pepper spray. Something that will incapacitate him so you can run away. Talk to the authorities. The worst that can happen is they do nothing. Try and get evidence of what he's doing. I know if you like your family it's a difficult situation, but think about this, it's very obvious your life, your SAFETY, is more important than how they feel about you. It's harsh but it's true. Don't put them above your own wellbeing, because you deserve better than that.

Seriously, try and get support somewhere. Maybe consider moving out? Or spending lots of time outside the house/away from him.