My little brother thinks he can do what he wants, and my parents just look the other way...?

He even goes as far as spitting at me and trying to hit me with a heavy object. I would retaliate but that would end up with him crying and me in a lot of trouble. I am 16 and he is 13. He should be mature enough to know better but apparently not and I am getting seriously fed up with this. Also my parents like him a lot more than they like me and don't address the situation at all.