If he's in an actual day care, he wouldn't need to be potty trained. They'd actually potty train him there and it would be successful because of the consistency. If he was in a preschool he would need to be potty trained.I think J, at his age, would have to be potty trained to go to daycare. He should have been feeding himself long, long ago.
They all be in for a HUGE shock the day he starts school, if he even does. They will probably just have him homeschool because they're obviously too used to their travel lifestyle.