T.D.
Well you have missed his window of interest some time in the last 2 1/2 years. In the day care I worked in we just told the parents to put the child in underwear all day long and just took them to the bathroom every 15 to 30 min. We also had them take off their own wet clothing and put new clothing one. They usually get tired of all the fuss and start having less and less accidents. Once they are in underwear DON"T put them back in pull ups except at night (until there are very few accidents) for any reason. It confuses the child and their bodies. Don't give up or give in. Besides children continue to have accidents from time to time until they are 5-7 years old. Also focus on the positive and don't punish the child for accidents. Maybe use a reward system you both can agree on.