What is presidential disability?

It is when the President cannot perform the duties of the president. And can voluntarily and temporarily transfer executive powers to the vice president.

Answer: in the event of the President's "Inability to discharge the Powers and Duties" of his office, "the Same shall devolve on the Vice President." This language was superseded by the 25th Amendment to the Constitution, ratified in 1967. Although there were several instances of severe presidential disability between 1789 and 1967, no Vice President sought to assume the chief executive's powers and duties during this period. Sections 3 and 4 of the 25th Amendment currently govern cases of presidential disability.