C.P.
I would try and move the nap up a bit. That's kind of late. My daughter wakes at around 7:30-8:00, and she goes down at 12:30 no matter what. I do have her on a schedule, but I do not wake her up, but her nap is so early, that I don't have the problem of her sleeping too late. It may take some time for him to get use to, but don't give up. Try and have lots of tiring activities in the morning so he will be tired at that time. Good luck.