What to do???????????????????????????

I'm 13, I live with my real mom and step dad. First, My half brother is spoiled, a slob, and cries too much. He will ask for something and if my parents say no, he will cry and cry and cry. They spank, but he will still cry. If he gets yelled at he will, try and find some way to get me or my 2 other half siblings in trouble. My parents spank,yell,put him in time outs, and take away his video games, but he still acts the same way. He has a xbox360 Kinect, Ps2, Ps3, and we share a wii. Also, he would try to still my laptop and Nintendo dsi even if I say no. I try to be a good role model but it's not working. He constantly beats me up, I hit back, but he doesn't give up until I get in trouble. I also forgot to mention, he doesn't take showers, brush his teeth, use deodorant etc., instead he use half my step dad's cologne which we are both allergic to. And he never ever cleans anything, but his plate. Spank spank spank, yell yell yell, discipline discipline discipline, he acts the same way. What can my mom and step dad do? Also what can I do to stop him from bucking up to me?