Unless you can really scatter the pellets, and I mean really scatter them, over something the size of a 4'x8' sheet of plywood with sides the horse will be continually without feed. If fed from a corner feeder or pail he can stuff his cheeks and send them down barely chewed. Unfortunately pellets don't hang around in the digestive tract very long and will soon exit. Then the horse has nothing to eat until the next feeding which could be hours away. He will chew the barn down, fence posts, boards looking for something to fill his need to eat. Without offering hay to tide him over he will develope ulcers. Omeprazole for horses isn't cheap so your dad can add in the cost of the vet, the scoping and the medication to his savings.