Gee he's real irregular and spontaneous huh?
LOL
Nah, I know its not funny.
My little Dude is 4. He still naps everyday in the afternoons.
If not he turns into an ugly fussy Troll!
It is just a daily routine since he was born he has always napped, and is a napper. To my glee.
He knows life as being no different. He has always napped.
And needs it.
Sooner or later he will grow out of it, due to not needing it or, him getting too bullheaded and powering his way through his tiredness, despite.
I stay in the room as my son settles down. The door is closed. If not he runs away and laughs at me!
I sit in a chair, do not engage with him, read a magazine, and don't even make eye contact. Every once in awhile I will look up and say in a soft monotone "nap...." and then he lulls to sleep. He tosses and turns first, then YAWNS, and I KNOW, that means he will drift off. And he does.
When kids are over-tired, some also get more 'hyper' and then they try to push their way, through that tiredness. But yes, they are tired.
As your son is, and by his falling asleep if you go anywhere in the car after 12:00.
Also, my son I have learned early on, he will NOT nap... if he still has to poop. Once he poops, he will nap. Nap is always, after he eats or snacks and poops.
Make everything dark and quiet and turned off and BORING before nap time, to set the stage. Tell him YOU are going to nap too. That is what I do. It calms them down.
Being perpetually over-tired, day after day, makes it worse and worse. It compounds.
Try some white noise maybe.
AND, important: start the nap routine AHEAD of time, setting the stage. Don't do the winding-down or routine, "AT" nap time, by then they will have passed that window of being able, to lull to sleep.
I get the nap routine and stage set, 1 hour, before the actual nap time. And I verbally cue, my son. Giving him a head's up.... so that he finishes playing, without getting all irked that I stopped him suddenly, in the middle of it.