Certainly getting him checked for sleep apnea would make sense. Does he snore? Of course sleep apnea can occur without snoring too.

http://www.drgreene.com/21_1189.html

Dr. Green mentions that children with sleep apnea may not get enough oxygen to their brain at night. If the brain is not getting enough oxygen, then it makes sense the rest of the body is not getting enough O2 either. Could that cause a morning paleness?

Could he be hypoglycemic in the morning? Are there any other symptoms of hypoglycemia such as sweating, irritability, shakiness, weakness?

Have you had his iron level checked?
Anne