V.G.
I would keep pushing him to 12:00 and see if he starts to sleep longer, at the same time I wouldn't give him another nap in the afternoon. If he needed one, you could only let him sleep for about 30 minutes. My mom works at a day care and I know that their toddlers only get one naps, some only sleep an hour, some sleep longer, it just all depends. At the same time, I know kids who are going into Kindergarten this year that still take one nap a day and both of my girls (4 and 5.5) don't take any naps. Sometimes it's just a matter of letting the child guide you. Good luck!!