The "Captain," is in Command of the Aircraft - from tip to tail.
The "First Officer," is 2nd in Command of the Aircraft.
The "Second Officer" (in the old days,) or now the - Augment First Officer - Cruise Relief Pilot - Second Officer, is 3rd in Command of the Aircraft.
If the Captain is not doing his / her job:
As per the Airlines (Standard Operating Procedures,) the Regulators (FAA's) rules, exhibiting abnormal behavior, is incapacitated by illness etc.
The First Officer is obligated to take Command of the Aircraft.
That is why they are there and that is why there is a "Chain of Command."
...you just - better be right!
I would fully expect a F/O, that is in strong disagreement with the decision of a Captain.
To do something about it.
For me, there is the question. Not ONE but TWO First Officers ended up on the ground in Miami.
Leads me to ASSUME, they agreed with the Captain.