Originally Posted by
Mjn
As long as he entered the real details of himself (name and birthday etc. mainly) he can get it back whenever he wants by scanning his ID and sending it to blizzard.
My advice would be logging on the account often and to afk around in OG or something so you get to include your IP in to his typical log in pattern. After you have been donig it for a while (~month or so?) just sell/delete/give away everything. Then change the password and/or add an authenticator.
The owner will report it as "being hacked" and Blizzard will see that the wipe you made came from an IP included in the log in pattern. They'll just say that they can do nothing since it was made by the account owner himself and, here's the cathc, they might think that the owner is trying to use the restore service to generate extra gold or duplicate items. And this is something Blizzard really, really despises.
So yeah, there's something you can do. But not much.