Apparently there is also no mechanism for getting rid of a president who can’t function.
Actually, there is.
However, it would involve Biden’s leadership, concurrence of the cabinet, and likely putting Biden into the Oval Office. Insupportable.
From Sect. 4 of the 25th Amendment:
“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. . . “