italia:
So when he said "propeller torque" and "engine torque".... he really meant "thrust horsepower" and "brake horsepower"?
No, you don't get it. Torque of shaft x revs of shaft = power, so it's the same as THP and BHP. I very much doubt he was talking about inertia, the way you asserted.
You could be creating 200 BHP, at a steady RPM, while stopped on the ground and your thrust horsepower would be zero.
Not that myth again. It's disappointing to have to point out to one who calls himself an instructor that in your 'brakes on' scenario the aircraft is still producing 200 THP as well as 200 BHP because it is accelerating a mass of air rearwards in a futile attempt to turn the earth and the atmosphere in opposite directions. Come on italia, pull your socks up. These are fundamentals that instructors should have a grip on.