Account Issue

This is pretty tricky and I'm not really sure to go about doing this.

I'm recently coming back to the game after an extended break I've convinced a RL buddy of mine to join me, but the problem is, we don't know his PW or account name. This is a little tricky, but perhaps with some background as to why we don't know this information, it would make sense.

He quit before the bnet account merge, so he's not sure how to request the password on his account since it's always asking for an email. He has access to the email, but when he logs on bnet, his WoW isn't attached to it because he stopped playing before they made us merge the accounts. We're fairly certain we know the account name (there were 4 accounts we made with very similar names when a bunch of us played retail) and it's even tied into my account (he did RAF and got me a zhevra)

So how can we request this PW back or merge it to his bnet account? It seems this is only a problem because all the log-in's require emails, and we hadn't merged his account to his email yet.