Where are all those news stories on 'fitness to serve' like there was for POTUS that kept asking if the 25th Amendment should be invoked for being 'mentally unfit'?

ROSS: Well, some people have been challenging President Trump's mental fitness to serve in office. And that's where the 25th Amendment comes in. Let's start there. First of all, what does the 25th Amendment say?

OSNOS: The 25th Amendment was created after the assassination of John F. Kennedy, when people in government realized that the Constitution was pretty good at dealing with the possibility of the death of a president. That's what vice presidents are for. But the Constitution was not well-equipped for another scenario, which was a president who, in Kennedy's case, had he lived from a gunshot wound, was comatose perhaps. There was no legal way for the duties of the office to be discharged by anybody else, so the government would be paralyzed.

And so in 1967, they introduced this amendment which created under Section 4 a pretty remarkable set of legal capabilities. And what it says is that if a president is determined to be mentally or physically unfit, unable to discharge the duties of the office, then he or she can be removed. And the determination about whether or not the president is unfit, that can be made by the vice president and the Cabinet.

https://www.npr.org/2017/05/04/526857048/trump-s-fitness-to-serve-is-officially-part-of-the-discussion-in-congress