I once lived at PO Box PML, Chignik, Alaska 995** for three years. At the time, very few in the lower 48 believed me, and I may have had a half dozen offers rescinded because of my Port Moller Location address. It is hard to send outside, and sometimes even within the US.
I am sorry this person has not shown more patience, but that comes with the territory, literally. I would not be hesitant to remind this person of where he is and how long it may take to even pass the most rudimentary of customs.
I used to send photos of the 1924 Port Moller Herring Chokers for encouragement...