I am assuming he is in a nappy at night?? Could you put him in a nappy for his day sleeps as well or a pull up and tell him that it is JIK?? DS still has a nappy for naps and night time and about 50% of the time he is dry for both but other times they are heavy wet so am assuming it will take quite a while for him to gain control at night and while asleep during the day.