He should go on xbox live and find out the email his account is associated with. This may actually be different than the one he originally used to sign up the account. He needs to make sure he is signed into this account on live.com before attempting to sign up on bungie’s website. If he has changed the email from the one he originally used to sign up the account, he might need to use the original one. Again, he needs to make sure he’s signed into live.com before going to bungie’s website.
