To what I see, it looks like he HAS a Bipolar Disease, AND, to my dismay, it's controlable via pills. Talk to your counselor, but I'd legaly force him to take a Bipolar Test.
Also, should he ever raise the hand, you could turn in for the cops, and then he could be in shite.
Also, you could ignore it, but it could have a permanent effect when you'll be older.
One more thing, where's your mother?