L.A.
What time does he take his nap?
If you want him in bed by 7 during the summer with all of the light and sounds of summer outside, he will need to be tired and have all of his energy played out of him.
Morning get up eat breakfast playoutside with lots of running, jmping climbing, peddling At leat 1 hour 1 1/2 hour is better, run some errands, .. a good hearty QUIET lunch, a quiet story and nap by 12 at the latest. Wake up at 1:30 or 2:00, snack, losts of play, swimming, running playing.. etc. for 2 hours, quiet time , calm dinner, NO TV, quiet bath, stories, bed..
If he gets up, he is returned every time.. Even at 4 in the morning.
If his room is bright, maybe hang fabric over the windows to make the room dark at night. Make sure his room is cool, and maybe get a sound machine. Get a gate for his door.
Consistency is the secret. Kids LOVE schedules and love stickking with it. Any changes will cause some rebellion.. Eventually it eill not matter so much, but at this age they really do respond best when each day is the same.