If he is backing out because of his problems then keep the money. If there was something wrong with the truck then I would say give him the money back. I got screwd out of a deposit I made on a truck. I really wanted the truck and he wouldnt hold it without a deposit. I told him I would buy it as long as it was good. Had a mechanic look at it and found the front axle tube was cracked along with other things like the tires had plugs in the sidewalls(had the tire switched around so they were on the inside). I told him there was problems to see if he would lower the price he said no and wouldnt give me back the deposit.
Dan