K.I.
All 3 of my kids stopped napping @ 2 yrs old (so did their father) and they function just fine. My oldest stepson napped til he was 3 and my youngest stepson napped all the way till 6, he really needed extra sleep and would just lay himself down after Kindergarten and some lunch and if he missed it he was a whiney/crying mess :)
My sister and myself grew up w/my grandma and she made us nap all the way til 4th grade...although we mostly just talked quietly!
My only suggestion would be to maybe move his nap time up so he is sleeping earlier in the day? Some kids get tired in the early morning and can take a quick nap either before or after lunch?