I've been wondering this myself. Why the hand? It makes no sense when there are other less obvious sites with easier access. The only thing I can think of is the IV runs while he sleeps. When he's awake he doesn't want the bag on a pole visible to others.

Bad veins at that age, often the hand is easier to get. At least that was the case with my dad

My guess is his veins are poor. Antecubital would be much easier to hide. I'm guessing they can't access those veins because they are either scarred or damaged.