I'll go out on a limb and vote heart attack or some such issue. Downside is we have lots of large carnivores that scavenge and bury things. Sorry to hear about it, sucks to loose someone especially the unknown of it all. Maybe another hunter will find something this fall to give family closure.
I was out chasing fish still when this first went down, but the wife was familiar with it. We usually go near there this week each year to chase Ptarmigan as the dog loves it. It's been absurdly wet this year and her schedule got goofed so we're not there.
They threw resources at this, even a coworker of my wife flew a few volunteer hrs as they were in the area with their plane. Never-mind the fact half the rednecks in the state were up their chasing nubbin caribou with every lower 48 sitka clad hillbilly that could drive and diy hunt. I'm always shocked at how many folks can crawl all over the area.
All that to say, this happens usually every couple of years. Guy strokes out or has a heart attack ankle deep in bog wearing camo clothes, year later they find a gun and half a chewed up pack. It's not some grand conspiracy or a Liam Neeson movie plot. Just a harsh reality of life. Hope the family finds some closure.
My families preferred exit is aortic dissection followed by cancer. Going out ankle deep in berry flat with half a caribou in my pack sounds alright by me.....
Satellite phones are wonderful things. I rented one the last time I went to Alaska to hunt. I think it was around $75 a week. Fortunately, I did not need it. I would not hesitate to rent one again even if I was going out with a guide. Of course, that is only helpful if you get lost or break down. They say he was going to get some meat from a meat cache a 1/4 mile away which they say he never made it to. He may have encountered a bear on the way. Its one of those things they always warn you about .