This really has more to do with unbiased account selection. The computer selects the accounts. And it's quite possible that whatever arbitrary date that Square-Enix selected for the cutoff he probably made just past that date.

Whether this date agree's with you is beside the point. In other words he got in just as legitimately as you will.
Keep in mind Alpha does not allow the servers up 24-7. They get taken down frequently for hot-fixes, and not all components of the game is active because they want the players to focus.