My brother was a fishing guide in AK.
He carried a 44 mag revolver.
By AK law professional guides have to carry
and the state specifies minimum calibers.
I believe 45 ACP is on that list.
One trip my brother took the lead and I had a 1911 45
(WWI 1911) and a 12 gauge as I followed up the rear
of our group. My job was to watch for any Bear tracking us.
We caught lots of fish. We were just catch
and release that day.
On the way back we could see where the Grizzly
(brown) bear had walked down our trail after us.
Enjoy your AK trip.
I think your brother was either confused on the law, or perhaps the laws were different then? I couldn't find anything specifically covering AK hunting guides.
Rifles, shotguns and pistols are all legal for hunting in AK.
However,
rimfire cartridges
generally can only be used for hunting small game.
To hunt
big game, with a
muzzle loader, it must be a
"
shoulder-mounted long gun and at least .45 caliber or larger
with a barrel that is either rifled or smooth bore and discharges a single
projectile."
[page 19]:
http://www.eregulations.com/wp-content/uploads/2019/01/AKHD.pdfExceptions exist for weapons-restricted hunts as well as bow and crossbow specs.
For example, during certain "muzzleloading firearms only" seasons, you can't use a scope or smokeless powder.
Based on that, I would say hunting with any centerfire firearm, long gun or pistol, is LEGAL regardless of caliber. Of course, dispatching the animal humanely is a consideration, but shot placement has more to do with that than caliber.