I'm assuming he's already been banned as a precaution - that, or his previous ban hasn't been lifted yet despite the recent ruling in his favor located in his dispute.
Regardless- the ban will remain until he has cleaned his computer, and he can be sure that nothing malicious remains in his system. Once this is done he can create a thread in the account recovery section appealing the ban, and he must provide sufficient proof to an Admin that he is in fact the original owner.
Credit to Necromancer for giving me the heads up on this.