There's a persistent meme on HN that it's straightforward to make a business that "runs on autopilot", with no human intervention. I'll admit that such a business is possible, but I'm deeply skeptical of the durability of such a business.

I'd much rather bet on a business owner like your dad, who's deeply involved. Sounds like your dad's receipt reading was a great habit to have, and paid dividends far outside of just "making sure things were running OK on a daily basis".