Reagan went through two cancer operations in office and had Alzheimer’s at the end. Churchill had a massive stroke and stayed on as PM for 2 more years. George Bush senior vomited on the Japanese PM, and the leader of the Canadian NDP ran an incredible campaign in 2011 where his party tripled its seats and became the leader of the opposition before succumbing to the Cancer he had been battling while running a successful campaign.
Not commenting on the positives or negatives of either candidate, but lets be serious about this episode.
BTW, uncharacteristically, Truump has been silent on this except to wish Clinton well. Either respect for 9/11, or smart politics, or both. Either way its a smart tactical move by someone who has shown tactical ineptitude with seeming opportunities like this.