He cancelled the appointment because he didn't want to either hang around DC for half a day, or come back a few hours after his appt to pick up the passport. Between me and you all, I think his priorities are a bit whacked.
However, about an hour ago he texted me a picture of his shiny new passport, so we're all good. I told him "congrats! You're no longer a loser!" (Yeah, it's fun being married to me - LOL!)
Thanks everyone for the advice and support. It was very helpful, and even the bits that I didn't use this time are I'm sure useful for next time (there better not be a next time for him!) or for others reading this thread. @:-)