C.V.
Hi J.,
There could be a couple of reasons that he is doing this. Has he always gone to bed late? Has he had a good bedtime routine in the past? If he hasn't you may want to start one. Both of my kids have a bedtime routine that may take up to a half an hour.
You also need to either make the nap earlier or eliminate it. My first son stopped taking naps around that time. He would want to take a nap late but I would entertain him until dinner (6ish) and then give him a bath and put him to bed. Sometimes as earlier as 6:30-7:00. He slept through the night without waking. Some days were harder than others to keep him up and it took probably a good 6 months until he adjusted. I would try and keep him up for an hour or two and then put him to bed. Good luck.
Chris