Usually, the registrar holds onto the domain for 30 days to give the customer a chance to re-register it.
However, if there is enough interest in the domain, they may not renew it and may submit it auction or to another person who has shown interest and wants to pay for it. Usually, the registrar sends out notifications 90, 60, 30, 15, 10, 7, and 3 days before expiration, and then on the same day they expire.
My guess is, he doesn't have the e-mail of record anymore, OR forgot his account information OR isn't checking the e-mail of record that it's expiring. He'll have to call and get back in to re-register, assuming they believe it's him.
I've already let network solutions know.. I'm interested in the domain.
