How to deal with watching a child s future be destroyed by family?

I have a very young brother. I know how damaging excessive (and i mean EXCESSIVE) screaming is on a toddler's brain in making them into a ghetto person. I have a family member who screams his lungs out every second of the day at the child. If my brother asks for, lets say, food or to go to the bathroom he screams. If he leaves his room he screams. And when i say scream i mean on the opposite side of the house with ear plugs in and my door closed it feels like he's screaming at maximum force right next to me. He screams at others as well… Now lets get to my mother. I just cant. Shes so ******* stupid - he literally hits, screams and degrades her every day. And its ******* hilarious because she tries to make him happy after he repeatedly disrespects her xD Also my mom works a day shift and I'm too young to drive him to daycare so he learns nothing. He's almost four. All he does is watch the violent cartoons they now play on cartoon network (not really that violent but for a toddler too much like teen titans go, ESPECIALLY UNCLE GRANDPA) and get screamed at for nothing. He has no authority figures or father, the person who watches him sits on her ipad all day and doesn't discipline him. What do i do? I want to leave but im too young to get a job. After three years of trying to help I've gained no support and my mom is "trying to avoid conflict" with him instead of helping her son. I feel so disgusted. How do I get the **** out of here?

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