15 hours ago, KenONeill said:

I don't suppose he's tried to prove it with a dry and wet compression test?

No

Perfectly legal to do in the privacy of your own home, just do not it in public with an audience. 

12 hours ago, Nab93 said:

No

In which case he doesn't know that the pistons, or even the piston rings, are shot. Change your garage.