B.M.
If he's advanced, but not *genius* (meaning he's going to be at the head of his class, but not quite advanced enough to skip grades), the one of the BEST skills you can teach him is how to challenge HIMSELF. Start that early. You can also teach him the lesson of *just because we don't wanna doesn't mean we don't hafta". You've enrolled him in PreK. That's a parental decision you make that is in his best interest.... and unless you feel *harm* is coming to him...... that's where he stays.
If he doesn't develop the ability to interact with other kids, take his turn and not come home and whine about school.... he's going to have a much worse time next year in Kindergarten... so don't coddle him.
Instead - try and instill in him the ability to be challenged in SOME way, even if he knows the material. Encourage him more to play with other kids, rather than how his counting skills are. Coach him on what to do if he wakes up from nap and naptime isn't over yet. THOSE are the skills he needs to learn in preK.
Those are the skills that will serve him well in the real world when he is smarter than the people around him. He will have to find a way to make the best of his environment
(she says while sitting in cubicle, typing on Mamapedia, surrounded by *sigh* idiots).