This happened to me several times. My brother would move out, times would get tough (meaning he spent all his money on booze and toys instead of rent), and he would move back in. Each time he came home, he just started the abuse all over again. Then he would get kicked out... and come home again.

I hope your parents know what's going on. But if they're anything like my parents, and don't care, then you might need to take extra steps to keep yourself safe. Do you think you could follow AShadow's idea and stay with a friend for a month or so? Taking care of yourself needs to be your top priority...