Moved this post since it was in an old thread and the wrong section so you could get some replies...
What you are describing is completely against FTP's (and any other poker site
's) rules. As soon as he tries to make a withdrawal, I'm sure it will be caught.
As for you and your brother, as long as you are each playing on your own accounts, and not colluding, chip-dumping, or doing anything else against FTP's TOS, then you're fine. Just to be on the safe side, you may want to send them an email just to let them know that you each have your own account, but live in the same household.