The 2024 Presidential election is likely to feature the two oldest major party candidates in American history. There may be a non-trivial chance that at least one of them becomes incapacitated before his party convention, perhaps even after getting enough delegates to be nominated.
Suppose it were Biden who was "hospitalized" (to the point of incapacity) after he won the primary. Would his Vice-President, Kamala Harris, automatically be awarded the nomination at the convention? Or could Biden tell his delegates to nominate any other Democrat of his choice (Michelle Obama, Gavin Newsome, or Robert F. Kennedy, etc.)? Or might the party make the nomination on its own since Biden would be incapacitated?
Suppose it were Trump who won his primary and became incapacitated before his convention? Would his vice-presidential choice be nominated automatically? And if he had not yet nominated a Vice- President would he get to name his replacement candidate to be ratified by his party? Or is there a possibility that Nikki Haley could get the nomination by being the last opponent standing when the front runner became incapacitated?
Edit:
My question goes beyond the other question as follows: If indeed, the results of a primary can't be ignored, what specific things can't be ignored: 1) The presence of a Vice- President or Vice Presidential nominee 2) A standing "runner up" such as Nikki Haley or 3) An express command by the winning delegate-getter for his delegates to back a specific other person.