M.R.
Is it possible that there is a paper delivery boy, airplane, train or some other type of noise that goes on that time or morning everyday? did you move his room to another side of the house..etc.. my son did this and we found out it was b/c the neighbors started to get the paper delivered..lol so he heard the car pull in and the lights would flash in his window..haha the best advise i have is to put him back to bed make sure he's ok or that everything is ok.. i wouldn't keep him up or lessen his naps b/c them being OVER tired can cause them to not sleep well. (i know it sounds weird, but it's true) also i would just lay him back down in his bed and tell him it's nite nite time.. and be consistent when you do this.. it should just be a phase.. stay strong..lol :)