[Former Fetus]

if the term "accident of health" is idiomatic for anything?

I don't know in Cuba, but in Spain it does not mean anything in particular.

BTW, the Spanish newspaper El Mundo is announcing that Fidel will have to spend several weeks resting, away from public view. How will we know when to celebrate?

[Socratic]

...several weeks resting, away from public view. How will we know when to celebrate?

When the stench can no longer be ignored.