What if he has to get out and cut a branch or limb with the saw, and cuts himself doing so ? He has to be able to fix himself up, as there's likely nobody with him. Removing brush from the brushing bar or deck of the drag, cut himself or fall, twist or break an ankle, wrist, anything. Gotta know how to do a proper splint to prevent the injury from getting worse.
What if he comes across a sledder who's had an oops ? He could administer first aid to the rider so as they could get out to safety.
Anyone who ventures way the hell out into the boonies, would do well to know basic first aid. Period.