If Biden died a week before the election , people would still vote for the Democratic ticket. Remember that when we go to vote we do not vote directly for a president but we vote for presidential electors.
I don’t know what happens if you have a deceased candidate who the electors are pledged to vote for. The electors Gather in each state to vote in the middle of December well after election day. Do they vote for the ticket they are pledged to and then the vice president becomes president? I wonder what would happen.
John Ashcroft lost to a guy who died when he ran for a senate seat in 2000. The governor replaced him with his widow.
That wasn’t a presidential election so not sure what would happen.
I believe the VP takes over
In 1872 Horace Greely died between the election and when the electors met. A lot of them voted for the VP nominee. Three electors voted for Greely anyway and congress threw those votes out
Get used to it.