What to do with an abusive brother?

My brother is physically, mentally, and emotionally abusive since he was a kid. There were times the police were about to be called on him since he hit other kids.

He has hit my mother in the past and he still mentally tortures her. He has physically abused me not only at home but outside too and there were CCTV cameras.

I have proof of him hitting my little brother but I am afraid to file a case since my mother is mentally ill and my father just wouldn't care about what he does anymore.

I am going to have another sibling and I am really afraid that he will be continuing this behavior forever and will be a threat to our family members.

I am genuinely tired of living in fear for myself and my family members every day.

Please help me to know what can be done on this matter legally!