Your best shot is faking a verification email to him asking for his first/last name...with the info you have that is all you need. After you get his last name just call blizz, say you lost access to account and email and forget your SQ&A they will then try to verify it another way, the way I have done before is they ask the two highest characters, what server/race/class/level. So logon, get the two highest chars and write that down. After you have email control (do it over the weekend for more time) xfer to a new account and perma ban the original. Have fun =D