That would be tricky. I'd think he was a deserter or AWOL until he was captured. Then his status became POW.
I don't like it at all. But to use a phrase from a Dylan song he was only "a pawn in their game".
He was indeed a deserter but the term is "UA" for 'Unauthorized Absence', no longer AWOL as in 'Absent Without Leave'. His 'capture' is irrelevant as he was not captured on the battlefield or at his appointed place of duty. As a deserter he is no longer a representative of the United States Armed services and not provided protections under the Geneva Conventions. He cannot be placed in POW status for 2 reasons, 1-Desertion 2-the Taliban are not signators under the Geneva Conventions and are not a uniformed service.
I had thought I read that several years ago, a military investigation concluded that he was NOT a POW, or maybe I’m recalling what I read incorrectly.