My daughter would not nap either at 2 and before! You've been given some great ideals, but after trying them and they still don't work, I'll share my story.
My daughter was somewhat out of control also: wouldn't sit still for me to read a book, always making noises w/mouth, a perpetual motion machine. The doctor ran some tests and found she had a chemical imbalance. She was given medication that she will have to stay on for the rest of her life.
I could not believe the difference.
The Dr. also gave us a list of specific foods. To detox her from any foods that was making her "crazy", for 3 days she had to eat peanut butter w/whole wheat bread, scrambled egg. wh. toast, and baked chicken. Milk, water, 1/2 water, 1/2 7-up. The Dr. told us to add 1/2 tsp. liquid calcium to her 7-up am and pm. (it acted as a calming agent) Her mind was going in 10 different directions because she was so hyped up on the wrong kind of foods.
The 2nd day!!!, she took a 2 1/2 hour nap!!! We kept looking in on her because we were concerned. We had no ideal we were giving her food that was like caffeine.
The foods the Dr. deleted from her diet:
applesauce (give apple, instead)
ham, bologna (no processed meats)
canned veg. (use fresh. Canned veg. have a dye that causes hypertension...even the red dye in Tylenol.
sweets
nothing w/white flour - pancakes, biscuits, gravy
crackers
no juices
no fried foods (baked, boiled, broiled, instead)
Although my daughter's hyperactivity wasn't diagnosed as ADHD, that is also a possibility w/your son. Hope this helps if all else fails. Good luck, you have my empathy.
P. S