What you can do, and it's something I did when I lost access to an email I had an account on, is to get the transaction number from when you bought the game. It would take some serious digging up in the bank account that the game was purchased with, but if you can do that, and get that transaction ID, that would be sufficient proof to have him update your email.
Then again, keep in mind that he did that for me way back in like, 2012, so I don't really know that he'd be up to doing that anymore.