Dumb question maybe re Stall Turn

Need someone to settle an argument. I do not fly, so your answers need
to be in laymans terms and hopefully put simply.
I've occasionally watched aerobatic displays and seen a maneouver
called a stall turn. Now, I more or less understand how this works,
but there comes a point, just before the aircraft "turns around" where
it is momentarily stationary in space, pointing directly to the sky..
Impressive stuff. Now, here's the crux: My mate reckons the pilot
could hold the aircraft in this "head-up" attitude almost indefinately
as the prop is acting like a helicopter's rotor and it could
effectively hover in this attitude. I, however, maintain that the
aircraft would begin to spin on it's axis if held in this attitude.for
more than a second or two.

Can anybody tell me who is correct?

Thanks all,

Roy