I cannot access my account - Gmail Help
If you can't work it out from there, you will have to set up a new account. You will lose all your apps.
If that does happen please remember in the future that this is a Google phone and everything revolves around Google and Gmail.
Hook, if he creates a new gmail and the phone is locked dosnt he need the username and password that was attached to the phone originally anyway? Or could you just sign in with a newly created one?
He can create a new account and use it, no problems. He'll lose his paid apps, but that's just how things go.