I’ve hiked in AZ, on more or less level areas and some of their mountains. I hope he had a pack with water in it just not shown in the pic. If he did that without water he’s both tougher and crazier than me - and that’s saying something! (well, the crazier part anyway)
The temperatures are moderate in winter, and the trail is an access road to the antenna farm on top of the mountain.
The view is from telegraph pass a nice 4 mile round trip in the cooler temps of winter not much water is needed. I have done the trip with many times with just half a litter and have had some left.