Just have him buy a savage axis 223 at the local sporting goods store. Cheaper than a #5 action, and no rebarrel needed. The $15 scope on it is plenty good to shoot a coyote at 80 yards.
Might as well give him a cheap expendable rifle, he's going to put it behind the pickup seat with no case, leave it leaning against the wagon in the rain and dew, stick it into a crack between bales in a haystack, use it to pry on a stubborn gate, and similar things anyway.
Been there, seen it, my dad worked on a very large sheep operation running tens of thousands of sheep. Used to go with him to deliver bread and groceries to the herders in the hills with their bands in the summer. I don't think I ever saw a sheepherder gun with any finish on it, and that didn't have leather or tin patches and black electricians tape holding the stock together. Don't remember a scope on one either, but those sheepherders are 55 years older now, probably need one by now.
I remember one complaining that he couldn't hit a coyote with his rifle. It was missing the front sight, all he had was the rear sight. The front 6 inches of the barrel was scratched all to hell. I asked him what had happened, and he told me he had been trying to pry a rattlesnake out from between some rocks. Absolutely no idea why the hell he was trying to do that. Probably because he was a sheepherder.
Also remember seeing more than one of them sharpening a knife on a convenient rock, by dragging it back and forth axially over the rough rock edges. Knife blade looked about the same as that rattlesnake rifle barrel.