well, he would need to buy a freewheel remover tool.
then need an adjustable wrench (unless the cheapskate magically has one)
then need the cog and lock ring (assuming he has a hub that has the opposing lockring thread)
then he would need a lock ring tool to make sure the lock ring is securing the cog on.

But that avoids the question of how to be stupid and defy all common sense like the OP asked.

remember kids, there's no such thing as a stupid question....

...........just stupid people who ask them.

ouch! twice in one night! that don geezee is a total c.unt