The parents do not sit around and teach him 24/7.
Unless you consider him asking them how to spell words, or asking them to write numbers on paper. It is all the little boy's request to learn, learn, learn. During free play, he only really plays with numbered blocks, putting them in order, making words from flash cards, or getting books and counting the page numbers in it. Seriously, he does this with novels just to count the pages.

As far as making him play more with the youngest child, I have 3 boys his age (within 2 months), a 4 yr old girl, and his 15 month old sister. He plays with her at home every night exclusively.

The nap deal. He will NOT sleep, at least not every day. maybe once a week he will actually fall asleep. I agree he is extremley young to not nap and his body needs it. but thasts another topic for another day!! LOL