Tell your stupid brother to read this several times:

http://runehq.com/RHQSpecialReportsView.php?id=00218

And I do mean stupid ........................keyloggers don't just "happen" either you have inadequate physical security and/or you are running an insecure setup, and/or generally coupled with unsafe internet usage practices.

Then read the security tutorials and posts on this site and learn how to secure the machine and install appropriate countermeasures.