I know it is hard, but like someone else here said, you just have to ignore him. If he is doing it to just to get to you, and you react, then he will keep doing it because you are giving him the reaction he wants. I know people who have personalities like this. They can usually dish it out but can't take it!!
I have a big brother too, so I can sympathize, LOL!!! You gotta love 'em.