He did right. It may not run well until you use up all the gas and refill it. It may knock, ping, gasp, hesitate, etc, but it should run well enough to drive. It may even take a couple of tanks fulls of good fuel before it starts running ok again. The cleaning fluid will help some. Probably should put some in the next tank full as well. After a few tank fulls of gas it would be a good idea to change out he fuel filter on the car.

A small amount of a tank full of petrol isn't a problem. There is enough petrol in the mix for the engine to burn the fuel.

Keep topping up the tank as it goes down and the concentration will gradually get less until it doesn't matter.

What country do you live in that $3.65 buys 2 gallons of diesel fuel. One gallon is closer to it. One gallon is not going to hurt it since he did the other steps. It used to be you could not get a diesel noozle into a vehicle that burns gasoline so things like that did not happen.

$3.65 is 1 gallon and mixed with 15 or more regular it should not cause an issue. Don't yell at Dad.....

THE NOZZLE SHOULD NOT HAVE MADE IT PAST THE RESTRICT-ER BUT THE GAS SHOULD BE FILLED UP TO DILUTE THE STUFF IN THE TANK. IT WILL MAKE FOR ONE HECK OF AN OCTANE BOOST. THE CAT MAY HAVE ISSUES AFTER THOUGH.

will it will work, but it will damage your engine very badly