1) Assuming you did get PPR that soon, no it doesn't matter where he's sending it from. People "visiting" in Canada send it from there all the time. Buffalo has specific mailing instructions for people mailing it from Canada who want it returned to them in Canada when it's ready; these instructions will be included in his passport request letter.
2) It usually takes about 2-3 weeks to receive the passport back in the mail from Buffalo. Once he has it, he can either drive to the nearest border and flagpole to land, or schedule a landing interview with his local CIC office if he still has valid temporary status at the time. Local offices tend to be booked up though and, depending on where he is, he might have to wait a few weeks or so for the landing interview.
Thank you Rinnerz.
Just a couple follow-up questions.
I was under the impression if we mailed it into Buffalo, we could pick-it up? But your response leads me to believe, if we mail it in then it's mailed back.
So when we get the request for passport, could we drop it off to Buffalo and get it back at the same time? We are only about an hour drive from Buffalo. If we drop off the passport to Buffalo, do we need to make an appointment, or just show-up?
Also, my husband is currently a permanent resident of the US/greencard. When he lands, does he have to turn in his permanent residence/greencard status?
Again, many many thanks to you.