How to deal with a 10 year old who has violent temper tantrums?

I live in a house with a single mom her 3 boys and their grandpa. Both the adults have health issues, that's why I'm living here. Anyways, whenever we ask the 10 year old to do something he either throws a temper tantrum or gets his brothers to do the work for him instead. And its simple things like emptying the cat box or bringing laundry downstairs. When he throws a temper tantrum he gets really violent. He throws toys, books, remotes, anything he can get his hands on. He also bites, claws and throws himself on the floor making us carry him upstairs to his room and then proceeds to grab the door jams and such on the way up while kicking us also. His mom has had past allegations of beating her children even though I can ure everyone that she does no such thing. We have tried putting him in his room with nothing but his bed or grounding him from movies or video games. Last Friday he was shaking his bed so hard after we had to carry him upstairs that he busted out his bedroom window. He also picked up a transformers plane and threw it at me, almost hitting me, when I'm 3 months pregnant. He has been suspended for biting and hitting a girl on the way to school and for threatening to punch his teacher for not being able to use the pencil he wanted to use. He acts out and cries in front of the other kids and we are all worried that he is going to teach them to do the same thing. But at this point we don't know what else to do about it. Help us...SOS...anything...please!!!