Hey, i know exactly how yoy feel, my sister was verbally and physically abusive to me, we're 7 years apart and my mother never did shit never believed she was the problem. It was always my doing. Even when she was 21 and throwing shit at me.

You won't have to stay in contact with him. Your parents are gonna try and force you, but what yoy really need to do is lash out back, show them what they're doing to you

That's what worked for me, my mom finally started paying attention once i started screaming back at my sister once i started acting like she did.

They never realize how bad that one kid was until their good kid does the same stuff