They said they would have been eaten by wolves. I don’t understand why they didn’t tie the man and the rebel boy and send the younger one down. It would have at least bought them another 1/2 hour.
I consider it highly unlikely that wolves would prefer humans to the goats that these three were herding. Wolves are generally afraid of humans, and for good reason - the ones that aren't end up extinct after wolf-human encounters. Besides, there are limits to how considerate you can be of foreign civilians. They weren't a SWAT team back home. Every Afghan civilian in that region was a potential hostile, and that went double for the males.
They could also have tied them up and suspended them from trees. Wolves can’t climb trees.