My brothers a psycho!!!?

My brother is psycho. He still lives at home even though hes 24 and acts like a complete jerk. He eats all our food and terrorizes me in front of my friends. Hes even gottan my friends to go along with terrorizing me. Because he scares them too. He'll hold me down and get my friends to punch me. And the first time I ever decided to drink I got way too drunk and ped out when I got home. I woke up tied to my bed with peanut er all over me, he had gottan my friends to help him do this and take pictures and than tried to blackmail me into doing **** for him with the pictures. Thats just one example of the stuff hes always doing. I wish he would just stay out of my life and move away! What should I do?