I think I would get into a specialist ASAP instead of waiting one the Ped just to be on the safe side. If you cannot get in right away, still go see you Ped but keep your specialist appt for sure. I definitely think his blood sugar is too high going from the sounds of your comments. Make sure you take his blood sugar before he eats to get an accurate reading, always use an alcohol wipe to clean the area before testing as any food or substance on the testing could cause a higher reading if not clean, and test before meals and just before bed would be my opinion.
Take care, K
Chances are he will prove to be Type 1 diabetic. 269 is way too high 2-1/2 hours after eating. Type 1 diabetes is an autoimmune disease - different than adult-onset type 2 diabetes. As the doctor said, keep track of his blood sugar for a few days and call in the results. And they will tell you what to do from there.
Maybe ask the doctor about the connection between gluten (found in wheat, barley, rye and possibly oats), cow's milk products and type 1 diabetes. I've read that these foods can in some cases be the cause of type 1 diabetes - but definitely not always - just sometimes.
Hang in there! Hope this helps.