Tomo Stryker said:
This is a gaming website, not yahoo answers. Please take this somewhere else.
I second this notion. This isn't 4chan where you get internets for saying fapping, and it's not yahoo answers. If you had a pertinent question that was intelligent, maybe a the morality of the situation and not just "what should I do" I would give you kudos, however this just isn't the kind of website for this kind of thread. If I'm wrong in thinking this please, anyone who is an escapist veteran let me know.
However I will try to answer your question because I'm not trying to be a dick
My advice is to talk to your brother, depending how old he is, I'm sure he does it to, appeal to that probability. Just talk to him about it, let him know your fears about telling you parents, and if he tells them then that means he was going to tell them anyways, so at least you tried.