Mostly just let the parents find out for themselves that it is not working. Just because they start in the summer at home - evenings and weekends, doesn't mean you have to do it at daycare till you feel the child is ready to cooperate in a group environment which can take longer to happen.

Mostly with special needs it can become a clock method where they don't always associate the need to go with getting to the bathroom and doing it so they are put on the potty every so many minutes and given the chance to go.