I have that problem, too. Especially once it gets cold out. My feet get so dry, I always wear socks and shoes, even in the summer and even in the house. When I go to someone's house and they have a "no shoes" policy, I bring along a pair of slippers that have rubber soles so my feet still have protection.
One thing that might help is, before bed, soak his hands & feet in a salt water bath, rinse them off, then put Vaseline on them, and wear socks and gloves to bed.
Another thing (and it sounds strange, but it does help) is if he gets severe cracks, put a drop of Super Glue in them. It helps seal the wound from dirt, sock lint, and keeps it from hurting. As the crack heals, the new skin will force the Super Glue out.
If the grass looks greener on the other side, maybe it's time to start watering your lawn!