We have a friend that regularly crosses the border for work and family. He had been unable to cross for about two months, but got through on a recent weekend using some extenuating circumstance excuse. I don't think there's any reason to discuss firearms, once you show a DL, they probably know all arms that're registered to a person. Just say no when asked if there're any guns, the more elaborating without asking, the more interested the border folks become.

Why not call a few of the area FFL dealers and see if they'll accept from a private party. Except for the cost of mailing, they'd probably transfer the 870 to your boy for twenty bucks?