That's what I said earlier in this thread. There have been some morbid things in this forum.
What happens if your opponent dies at the chessboard ?

What if your opponent actually turned out to be a store mannequin and not actually a real person at all ?

What if the guy died, but his spirit continued to move the pieces and stop the clock, while the body lay motionless ?

What if the guy died, but his spirit continued to move the pieces and stop the clock, while the body lay motionless ?
Tobacco and spirits are banned from playing areas usually....

What happens if your opponent dies at the cheeseboard? You would go crackers!!! Wheeeee!!!!
I didn't know competitive cheese eating existed...

I think it's a good idea to make it a draw. That way there is no motive or incentive for the opponent to see to it that their opponent has an accident. The outcome can be decided by fair play over the board without any funny business.

Perform a séance and finish the game.
Unfortunately, FIDE doesn't allow substitutes for a game. If the person cannot appear in person physically and play the game themself, the game is forfeited. Other people are not allowed in the playing area. And definitely, nobody is allowed to suggest moves other than the competitors, even if the person does claim to be in touch with one of the competitor's spirit and speaking for the competitor. FIDE is very strict about these things.
There are partial precedents.
When Reshevsky was playing Fischer and the flags fell, Reshevsky's wife tried to claim a time-forfeit on behalf of her husband... on the grounds that a man and his wife were "one flesh" according to the Bible (Book of Mark, 10:8).
According to two sources, Reshevsky's wife shouting about his flag happened in a game with Byrne, not Fischer. Not that it matters much. And well, I can't rule out the possibility that she made a habit of this and did it with Fischer too; I just can't find a story on it.
Here are the links - look for comments as described:
First link Look for Ian Burton's comment 10/12/03, who witnessed the incident.
http://www.chessgames.com/perl/chessgame?gid=1044313 Look for comment "Feb-26-10 Petrosianic".
These two sources disagree however on the results; one of them says that the game was ruled as draw, but the other says that her husband was there and claimed the game. What happens if a player claims but another person was first to point out that the flag was down? Is his claim valid in that case? Because if it's not valid when he wasn't first to mention it, then maybe both sources can be right - Reshevsky might have claimed the game but arbiters ruled a draw.
Oh Dear