Washington — Douglas McCain, the eldest son of the late Sen. John McCain, has died, his family announced. He was 66. 

"I am deeply saddened to share the news of my brother Doug McCain's sudden passing," Meghan McCain said in a post on social media Saturday. 

McCain died suddenly on May 20, his obituary said. He was the son of a military hero who had a long career in the Senate before his death in 2018 after being diagnosed with an aggressive form of brain cancer. The younger McCain flew A-6 Intruders in the Navy for six years before going on to work as a pilot at American Airlines. 

"He was a truly wonderful, joyful man who supported me throughout my life. He brought humor, fun and great conversation to every room," Meghan McCain said. "I will cherish our memories together."

The McCain Institute said Saturday that McCain "will be remembered as a patriot and friend to the many alumni of Sen. McCain's Institute, campaigns & Senate staff."

He is survived by his wife Ashley, his two children, Caroline and Douglas, and his mother, Carol Shepp, along with his siblings and step-siblings. John McCain adopted Douglas after his marriage to Shepp in 1965. John and Shepp divorced in 1980, and he went on to marry Cindy McCain.