When a sitting President becomes mentally ill, delusional or other conditions that impair judgment putting people at risk, the US Constitution provides a means to remove them from office. There is a simple process that is similar to impeachment, however the focus is on mental health and not an impeachable offence.
When taking into account mental health and often reading in the news about someone who went off the deep end on a killing spree, the concern about getting weapons out of their hands becomes a topic to talk about and take action on. Having someone march into a school with an AR-15 killing young students and teachers is bad enough, but exchanging that AR-15 for enough nukes to kill everyone and everything on the planet several times over makes it everyone’s concern.
On July 6, 1965 Congress proposed the 25th Amendment to the constitution to address just such a concern. The nuclear weapons age was here and the potential of giving the launch button to someone who was not in contact with reality was a grave concern at the very least. The amendment was signed into law on February 23, 1967.
In simple English the 25th Amendment says the following:
Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President.
Thereafter, when the President transmits to the President pro tempore of the Senate and the Speaker of the House of Representatives his written declaration that no inability exists, he shall resume the powers and duties of his office unless the Vice President and a majority of either the principal officers of the executive department or of such other body as Congress may by law provide, transmit within four days to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office. Thereupon Congress shall decide the issue, assembling within forty-eight hours for that purpose if not in session. If the Congress, within twenty-one days after receipt of the latter written declaration, or, if Congress is not in session, within twenty-one days after Congress is required to assemble, determines by two-thirds vote of both Houses that the President is unable to discharge the powers and duties of his office, the Vice President shall continue to discharge the same as Acting President; otherwise, the President shall resume the powers and duties of his office.
The President can’t be removed from office for this by a Congress complying with the Constitution. However, the VP and the majority of the Cabinet can say “he’s crazy,” at which point the VP takes over the duties as Acting President. Congress then decides whether or not he’s crazy. If Congress agrees, the VP continues to act as President.
https://en.wikipedia.org/wiki/Twenty-fifth_Amendment_to_the_United_States_Constitution
