Up at 7 am, can't hold his eyes open by 8 pm. Been tested for sleep apnea, had nasal reconductive surgery, levels tested & normal. Y is he so tired?

Good question. Hard to give any answers without reviewing all the tests done. If suffering from sleep apnea and symptoms despite treatment, medications are available to promote wakefulness.
Specialist? Has he been evaluated by a board certified sleep specialist? Complex question. Work with an expert to determine cause of problem.
Sleep apnea. Was he tested with an overnight witnessed sleep study, or just a finger pulse oxygen device? An overnight study is necessary to diagnose sleep apnea . Has he had tonsils and adenoids removed? Does he snore? Wet the bed? All are signs of sleep apnea.