I'd have both your son and his wife go down to the local police department and each get a license to purchase, carry, possess, or transport pistol. They are good for 30 days. When he wants to carry the pistol, have his wife transfer it to him. He has 10 days to turn in the LEO portion of the license recording the transfer. Then, when his wife wants to possess it again, transfer it back and send that one in. If they each have each used their licenses within the 10 days, they should go down and get another one. With the licenses now being valid for 30 days, I'd just always make sure they each had a valid license and just keep using them every time, switching back and forth. Sure, during any month they may have multiple transfers between the two of them, just make sure each has a valid license and do the transfer. I'm sure the PD will just love your son and his wife swamping them with paperwork... but they'll be following the law...so the LEOs need to just deal with it.