kerosene, now that's an interesting one. Depending on how long it sat in the tank, lines, carb bowl will determine how much cleaning is needed. Because kerosene has higher lubricating qualities than gasoline, your safe with that. the coating will wear off and probably foul a few plugs, so buy a couple spares. i'd pull the plug and see what it looks like after running it, remember that when you let it idle it will change the color, it should be mousy brown.
i'd take the carb off or at least pull the bowl plug and run gas through it / let it sit full a day / drain it a couple of times. drain the oil and see if there is any floating in the drain pan, other than that unless a chemist out there has some details deeper than most of us common sense types, your good.
Just because he said it was never started does not mean kerosene didn't work its way into the motor.
good luck
Doogie