Help????????????????????

My name is Damien and i have 2 older brothers and 1 younger sister. my mum died after my sister was born 5 years ago and my dad being a single parent went mental and started doing terrible things, he now got a life sentence in jail for abusing us, my oldest brother is 18 and took custody of us so we wouldnt have to be split up in different children homes, but he doesnt know a thing about taking care of us, he doesnt know how to cook so we are always starving, hes hardly ever home, my sister just stares into space all day, im so scared and angry after what happened, i dont know what to do. i go through the whole day with silent, i can never find the right words to say and when i do i end up yelling it, but thats not very often, i just dont feel like talking to my brothers and sister, can anyone on here help me or give me some advice? please, im so scared, what if my oldest brother turns out like our dad? Any advice? Thanks for all who answers this question, it means alot to me.