K.A.
This is normal in siblings. I have a 5 year old boy and a 17 month old boy who fight over things. They mainly do it when we are in the store, but it happens. All you can do is talk to them. Tell them they will be grounded if they don't stop. Try seperating them. Also try and reason with the older one, because honestly he should know better. Your older child is 11 mine is 5 and I tell him this. He stops for awhile anyways. Yours will be easier to talk to though. He may be starting to feel like he is a teenager and he doesn't want his little brother hanging all over him. Did this just start or has it been going on for awhile? Seperating the boys for awhile is your best bet. I wish you luck.