There was no aborted takeoff. The aircraft never left the taxiway.
This guy had a pretty checkered history to begin with, including at least three documented instances of being on the clock with two different airline employers simultaneously, one of which was American. Why AA hired the guy and then kept him is a question one might ask. Falsely reporting time worked is a termination offense with any employer I've ever heard of.
That this guy did what he did makes it clear that he intended to force cancellation of the flight, since the crew would have noticed the problem well before takeoff, as they did.
In the worst case, had the aircraft taken off, there would have been no real risk.
The engines, the wings and the control surfaces couldn't care less about an inoperative pilot convenience feature and the crew would have been fine on the backup instruments, since the crews of the US majors are both well experienced and well skilled., unlike those of certain other nations.
Why this guy did what he did is an open question that has nothing to do with his stated desire for a little OT pay.
American has been locked in a bitter dispute with its tech union for some years now and has numerous aircraft grounded at any given time due to the lack of union members willing to take OT in the absence of a contract settlement.
Had the guy wanted OT, it was readily available, especially at MIA which is a hub ruled by AA.
I suspect that this fellow has some other issues between his ears.