What do you mean when you say that he doesn't want to go to sleep until 10:30? Are you still putting him to bed at his normal time?
Occasionally my dd wakes and just needs to be comforted before going back to sleep for the rest of the night/morning. It is not all that common, so when she does do it, I just see how long it lasts... if it would start to be day after day for a week, I might worry that we are starting a bad habit. Usually, we see a reason within a day or two... either sickness or teething. Other times, she just goes back to her routine, so I'm not sure if she is having nightmares or is maybe frightened by a random noise... who knows, but because she is an independent sleeper, we usually get right back on track.
How long has this been happening? Is it still going on or has it passed already?
If you start to get the feeling that he is waking because he is just plain hungry, then up his calories during the day and see if that helps him.