The aide, Kelly Sadler, had made the misguided remark, reportedly intended as a joke, almost a month ago.
Kelly Sadler's comments about the Arizona Republican, who has been at home fighting brain cancer, sparked a weeks-long saga after they were made public last month.
White House spokesman Raj Shah today said, "Kelly Sadler is no longer employed within the Executive Office of the President".More news: MyHeritage DNA testing service says breach affected 92M users' data
At an internal meeting last month, Sadler had said that McCain's opposition to President Trump's then-nominee for Central Intelligence Agency director, Gina Haspel, didn't matter because he's "dying anyway".
Citing "three sources with knowledge of the matter", CNN disclosed that Kelly Sadler, who worked in the Communications Office, was relieved of her duties Tuesday.More news: Trudeau tells premiers U.S. tariffs 'unacceptable' as Trump's G7 looms
Sadler's exit comes after accusations from McCain's daughter, Meghan McCain, that Sadler had apologized to her privately and then promised to do so publicly but failed to ever do so. McCain's wife Cindy also tweeted to Sadler,"May I remind you my husband has a family, 7 children and 5 grandchildren".
The White House did not say whether Sadler had been fired or left the job voluntarily. "It's being addressed internally and I don't have anything further to add". He recommended that his fellow senators vote against her, but the Senate confirmed Haspel 54 to 45.
"Ms. Haspel's role in overseeing the use of torture by Americans is disturbing", McCain said in a statement.More news: Gmail's major redesign will be available to all in July
Trump, for his part, once mocked McCain's war service, saying during the presidential campaign that "I like people that weren't captured".