How could an FO not have practiced this? It simply isn't possible to practice incap procedure if the FO can't stop the a/c!!!
It is when the 'tick in the box' incap exercise starts in the air during gear or flaps up and finishes when PM call the CC's.
I would hope you would do what you briefed.
It has come up in the sim - and I don't recall being in an operator where a RHS RTO has not come up (I've only ever operated where if RHS is PF then they have control throughout the takeoff)
And therein lies the rub. I've never worked for an airline where RHS can call stop or action an RTO. Hence it is not briefed. I've worked for only 1 company with RHS tillers. I've only worked for 1 enlightened company where the incap was during takeoff roll and RHS made an RTO and then stayed on the runway as no tiller. There was never ending discussion whether they were allowed to take a hi-speed exit using rudder pedal only. It is possible as I used to demo on LT, as an extra. I used to let F/O's taxi with rudder pedal only just to see what radius the a/c could make. Surely it's part of learning how to control an a/c, but evidently not when suggested to HOT as an LT syllabus item.
The debate whether to stop on runway or vacate will rage on for pages, I'm sure.