Be nice to him and treat him well. If he becomes violent when you are playing, tell him you do not like too be treated that way and will not play with him until he says sorry and is ready to play nicely. Then take some toys you want to play with and go to a different room or a different side of the room to play. Ignore him no matter what he says or does and he will get bored and stop. When ever he does play nicely, thank him for playing nicely. And say "see how much fun we can have when we play nicely?" Make sure you are not leaving him out of games that you and your other brother are playing and that everyone plays fair. If he is being left it or mistreated, he may resort to violence because he does not know how to appropriately express his feelings. If he hits or says naughty words, hold his hands and say "you may not hit me. It hurts and I do not like it. I am ready to listen to you when you stop hitting and use nice words to tell me what you want." Then ignore him until he apologizes and speaks to you respectfully. If he takes a toy from you, while you are ignoring him, go play with a different toy. Don't even react. Do your parents know he acts and treats you and your brother this way? If you have their permission, when he hits, hit him harder than he hit you and say "see? Hitting hurts. Don't hit me and I won't hit you."