Thanks for providing more information.
As per your description,his daytime sleepiness,fatigue,lethargy shouldn't be ignored and it's good to see your family doctor for a clinical examination and undergo further blood work like CBC,ESR,Thyroid function test,Vitamin D,Serum Electrolyte,Serum calcium for further evaluation.
Possible differential diagnosis may include Anemia,Thyroid dysfunction,Hypercalcaemia,hyponatraemia,Narcolepsy,altered cicardian rhythm,increased stress,atypical depression and sleep deprivation/lack of deep sleep apart from sleep apnea syndrome.
I understand your concern regarding your son and it's strongly advised to evaluate his symptoms to get proper treatment.
If leave them untreated then it can get chronic or worse over the time.
Hope this helps.
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