Is he driving up or flying?.....maybe the ferry?
Driving Penske truck
Is he doing a full Do-It-Yourself (DITY) move or a partial DITY? Makes a difference.
If he is doing a Partial DITY move he can ship firearms with his household goods that the Govt contract mover is handling - probably best way to move handguns or any longuns that run up against Canadian prohibitions. The movers have pretty strict rules for documenting and accounting for the firearms. Make sure they are correctly inventoried and documented in the moving contract. When I did ship with movers I removed bolts from rifles and packed them separately - at least if some asswipe stole them they'd be useless. Pretty sure the contract movers will not ship ammo.
If he is doing a full DITY move he needs to really dig into the Canadian rules of what they'll allow to enter the country, and follow US Customs rules and paperwork so he can get them back into the US when he crosses into Alaska. Pretty sure handguns will be a major problem/no-go!
When I PCSd to AK many, many years ago they gave me a set of NATO travel orders in addition to my regular Army travel orders - don't know if they still do that - made the border crossing pretty easy.
It isn't worth the risk to try and hide anything that Canada prohibits or to try and skip the paperwork - won't just delay his crossing but will also royally piss off his Commander if he screws it up.