I really don't know what to do anymore... Help!?

I'm 14 years old. I live with my younger brother (10 years old) and my parents. My brother has autism (aspergers), and doesn't go to school anymore. Ever since he's been diagnoses with aspergers, he's been beating me up badly, at least once a week. This morning he came and pushed me to the ground, kicked me, and attacked me with a broom, he also swore pretty badly, I actually couldn't breath, thats how bad it is, and he has a friend that encourages him, and cheers him on. I told my mom about this, (we were home alone when he beat me), and it's not that she didn't care, she just didn't do anything. I can't stand living like this, some days I consider suicide. What do I do?