That’s unusual. That he got a good deal with cash.
Dealers do not want cash sales. They make far more profit on a deal with the financing.
Long story short. If you have the cash to buy a car, great. But don’t bring it to the dealer.
Make your best and cheapest deal on the car. Then go to the finance office and sign the deal. If they want to screw you for a high interest loan, so what? Sign it.
Then pay it off in full with your cash a week later.
Good advice.