My brother was sleepy all the time. It came to a head when he fell asleep at the wheel. Luckily the car drifted off the road onto a grass verge and no-one was hurt. Turned out he had sleep apnea - his breathing stopped time and again through the night, waking him. He never ever had a good deep sleep. He now has a CPAP machine that keeps his airways open while he sleeps. He says he’s a new man.