Sadler's remarks surfaced shortly after Thomas McInerney, a guest on Fox Business Network, sparked a backlash by claiming torture methods of interrogation "worked" on McCain.
"The fact is, is John McCain — it worked on John. That's why they call him 'Songbird John,'" McInerney said on-air Thursday morning.
McCain was a Navy pilot who was beaten in captivity during the Vietnam War.
Charles Payne, who interviewed McInerney when he made the comments, did not challenge the analyst at the time. The host later issued an apology on Twitter.
Mediaite reported Friday that Fox News had cut ties with McInerney, citing a spokesperson for the network.
Sadler later called McCain's daughter, to apologize for her slights against the 81-year-old Arizona senator, a source told The Hill.
Meghan did not respond to CNBC's request for comment.
McCain, who has spent three decades in the Senate, was diagnosed in July with glioblastoma, an aggressive brain cancer. He left Washington in December and underwent surgery last month for an infection.
Sadler is a special assistant to the president. She did not respond to the request for comment Thursday evening.
McCain's wife, Cindy, responded to both attacks on her husband in a pair of tweets Thursday.
The ailing senator has urged his colleagues to reject Haspel. He said Wednesday that he believes she's a patriot who loves the country but "her refusal to acknowledge torture's immorality is disqualifying."
Haspel faced grilling Wednesday by the Senate Intelligence Committee about her role overseeing some CIA operations after the Sept. 11 attacks. She told senators that she doesn't believe torture works as an interrogation technique.
As for the president, he and McCain have had a troubled relationship.
As a GOP presidential candidate in 2015, Trump said McCain was "not a war hero" because he was captured in Vietnam, adding, "I like people who weren't captured."
Last July, McCain became the deciding vote against the GOP health care repeal with a dramatic thumbs-down. Trump later told the Conservative Political Action Conference that "except for one Senator, who came into a room at three o'clock in the morning and went like that" — Trump gave a thumbs-down — "we would have had health care (reform), too."
The crowd booed, and Trump added, "I won't use his name."
The Associated Press contributed to this report.