i know how u feel, in my experiece, it is best to get out of the way. You say that u try to stop them but yet they still fight. This means if you cant help the situation (not that it is ur fault) then it is best to leave. Go for a walk, go to the back yard, just leave the fighting ( take ur little bro with you, its not really pleasent to have your erliest memories being ur parents fighting). Also it may help if you talk to them about how u feel. It doesnt mean they will listen but it is worth a try. Hope I helped. And dont worry, be a kid. Dont get mixed into ur parents problems.

stay strong!
-madstar