Hillary is sick. This is now a point that even the mainstream media cannot ignore. Her campaign staff claims it's simply pneumonia and it's getting better, but what reason have they given us to believe them?
What incentive do they have to tell the truth? The answer is: None.
If Hillary is truly sick with something more extreme, they are faced with an ultimatum:
End Clinton's campaign, or lie.
And the latter is far more appealing to any political strategist.