My whole life is a complete mess?

My brother is constantly behaving roughly and rudely with my mother, contradicting every single thing she says with irritation. My mother has not done anything apparently wrong, He nevefr communicates properly bout it even if she has done something wrong. I emotionally depened on him but now I am taking anti-physcotics and depressants becuase i cnt cos he is always an angry person and i am still dpressed. I could not ive with the atmosphere so i moved out. I feel scared to go near him when I mix with him. He is such a *nice* person extreemly agreeable person, and always was before three years ago and like my dad and my God. I dont have anyone else for confidence. This happened after we arranged marriaged him with a wife and we all live together(dont say this is wrong becuase everyone does this in our culture and works out fine). I feel like tthe whole of my life wwhich was based around him is mucked up, I want to die. I cant stand him harrasing my mum anymore, i want to die. My mum just ignores it and carries on normal..I brooke down and without his confidence i cant face any other people to befriend properly or trust people.