I don't use Vuze much.
How would I go about doing that gabryel48?
I could sneak on his computer.
Sadly, he is the PC Wiz, and is a very smart child.
He would probably notice the change in settings right away. It would take him 10 seconds to get the full bandwidth back. Closing ports sounds a little bit more promising. But you need admin access to your router for that. Better even if he doesn't have the admin password to it. If he has, he may lift the torrent port blocks just like the bandwidth limitation. Only it would take him a bit loonger to find the source of his dead torrents.
Going to up to him and open the Vuze window with all the downloads in it right after he told you he is not downloading anything might be the best way. Possibly with your parents in the room, if you think he might physically stop you from doing so. Do your parents use the Internet too? / Are they affected by this as well? It would make things a lot easier.