He drove over a subterranean stream, and the ground gave out and the truck fell in. He lives in permafrost country and it's how it is. Also he had better than a winch, he had another large truck and a giant bucket to yank on him, resulting in broken tow straps. Only way to avoid such situations is to stick to pavement if there were some. As he had posted he needs a large excavator to lift and re position the wheels on firmer ground. Not going to be an easy task. First you have to trailer one in as far as you can (semi truck with a low boy trailer) then crawl it to the site at a couple miles an hour, use big lifting slings and pray the windshield survives, I'd strap plywood over it somehow. Once in stuck all the equipment has to come back out, and you still have to find a way to get your truck to where you were going because you have a job to do. I hope favors are owed and can get out of this situation without breaking the bank.
Only way to get through those things is with a low ground pressure vehicle, something like a snowtrac (sorry I couldn't resist lol)