Stop brother using my ps3?

Constantly using my games, DVDs n stuff. I've got parental controls on strictest levels but somehow when I put I DVD it still plays? We both have our own ps3s be share a Tom. However there is only one USB control charger which is mine, so tonight I've too it with me and my remote. So when his dies he's screwed. This is only temporary though coz he will soon buy his own. What can I do?