Doug McCain, eldest son of Sen. John McCain, dies at 66

Doug McCain, the eldest son of the late Republican presidential nominee and Arizona Sen. John McCain, has died at 66.

The McCain Institute said in a statement that the junior McCain, a Navy pilot like his father, would "be remembered as a patriot and friend to the many alumni of Sen. McCain’s Institute, campaigns & Senate staff." An online obituary said Doug McCain died "suddenly" last week, but the institute, a nonprofit established in 2012, did not immediately confirm his cause of death.

The biological son of Alasdair Swanson and Carol Shepp McCain, he was adopted by Sen. McCain in 1966 after the longtime Arizona lawmaker tied the knot with Shepp McCain the year before.

The younger McCain, a Florida native, was raised in Jacksonville and later attended the University of Virginia, where he met his wife of 40 years, Ashley, according to his obituary. He joined the Navy in 1982 and spent six years flying A-6 Intruders. Later, he became an American Airlines commercial pilot, rising to captain.

Doug McCain was a father to daughter Caroline McCain Hendrickson and son Doug Shepp McCain Jr. McCain is additionally survived by his younger brother Andy McCain, who Sen. McCain also adopted, and their younger sister Sidney McCain.

Sen. McCain was later remarried to Doug McCain's stepmother Cindy McCain, and his stepsiblings include Bridget, Jack, Jimmy and TV personality Meghan McCain.

In a heartfelt social media post on May 23, the former co-host of "The View" said she was "deeply saddened" to share the news of her older brother's "sudden passing."

"He was a truly wonderful, joyful man who supported me throughout my life. He brought humor, fun and great conversation to every room," the "Citizen McCain" podcast host wrote. "I will cherish our memories together. Our prayers are with his wife Ashley and children Caroline and Shepp."

Sen. McCain died of the brain cancer glioblastoma on Aug. 25, 2018.

When asked about his father's legacy, Doug McCain told a Norfolk, Virginia, NBC affiliate that it was "to inspire people, to work for a cause greater than their own, and to recognize that America is an exceptional country, and that we are the world’s greatest hope for democracy.

Cindy McCain, who previously served as chief of the World Food Programme, stepped down in February to focus on recovering after she had a mild stroke in October.

Last week, she posted a photo of herself and her late husband on Instagram, sharing on what would have been the couple's 46th wedding anniversary that "I miss John every day and continue to be inspired by what he stood for."