Trying to Help my Dad

Hi, I hope it’s okay that I post here. To my understanding and reading the wiki, I don’t think this is narcolepsy, but I’m kind of at a loss.

My dad is mid-70s and we’ve noticed a pattern over the last few years as my dad ages. When he is inactive (meaning not actively engaging in something), he tends to fall asleep. He won’t necessarily wake up right away when someone says his name, but eventually does (these are usually about 5ish minutes). If he’s actively engaged in talking to someone, reading, etc., we don’t really see this happen. Just when he’s watching tv or listening but not necessarily engaging in a conversation.

Well, it’s now started to happen when he drives (about 3 times so far). If he’s driving some place that requires his brain to be active (intersections, turning, etc.), he seems fine. But a couple times now when he’s highway driving on long stretches of road and in the monotony of it, he has fallen asleep. My parents recently took a short roadtrip with friends and it happened. Thankfully his buddy was in the passenger seat and woke him up, and guided the car over to the shoulder.

He has agreed to go to the doctor, but seems to be denial or thinks the episodes are much shorter than they are. I don’t know if what he’s experiencing is a medical condition, medication side effect, aging, etc. I’m just trying to get us pointed in the right direction or if anyone experienced something similar?