That's an old trick for older diesel engines to help prevent the diesel fuel from gelling when very cold. It does not work as well on some newer diesel engines though.

If you bought the fuel in a cold state the fuel is already winterized. If not, a better and cheaper route is to add kerosene not gas as it could cause a fire danger. Not to mention more expensive. 1.5 to 56 would probably not be a danger.

Some vehicles in the colder climes run up to 50% kerosene.

Prbably be ok if you fill it up with diesel will be dilluted down enough for it be ok / still run

Call it anti-gel agent.

no effect at all.