Col. Bud Day, left, and Sen. McCain, right, talk during a campaign rally in 2008. (AP Photo/Charles Dharapak)

George E. “Bud” Day, an Air Force fighter pilot who received the Medal of Honor for his valor during 51 / 2 years as a prisoner of war in Vietnam, where he befriended his cellmate, the future Sen. John McCain, died July 27 at his home in Shalimar, Fla. He was 88.

The cause was complications from cancer, said his daughter-in-law Mary Ann Day.

Col. Day was described in news accounts as one of the most highly honored military officers in U.S. history. In addition to the Medal of Honor, he received some 70 military decorations, including the Air Force Cross, the Distinguished Service Medal, the Silver Star, the Legion of Merit, the Distinguished Flying Cross and multiple awards of the Bronze Star Medal, the Purple Heart and the Air Medal.

On Aug. 26, 1967, he was a 42-year-old Air Force major and father of four when his supersonic jet fighter came under fire over North Vietnam. Forced to eject, he suffered a broken arm, a knee injury and the loss of sight in one eye. He was swiftly captured, he recalled years later, by adversaries including a teenager armed with a rusty gun.

“I hit the ground real hard,” Col. Day once said, “and when I woke up, they had me.”

After interrogation and torture that included a mock execution and suspension from his feet, Col. Day enticed the guards to “relax their vigilance,” according to his Medal of Honor citation. He escaped his captors and began making his way toward South Vietnam, sustaining himself on little more than berries and uncooked frogs. At one point, he was wounded again by shrapnel.

Despite his injuries, Col. Day arrived at the demilitarized zone. After wandering for a number of days — a consequence of delirium — he spotted helicopters that were evacuating U.S. Marines. He arrived at the landing area just after the helicopters took off, according to an account in the book “Medal of Honor: Portraits of Valor Beyond the Call of Duty.” The next day, he was recaptured by the enemy in an ambush.

The Medal of Honor citation described Col. Day as “totally debilitated and unable to perform even the simplest task for himself” and credited him with answering interrogation questions with false information. He spent five years and nearly seven months in North Vietnamese prisons including Hoa Lo — more commonly known as the Hanoi Hilton — and one dubbed the Plantation.

Besides McCain, his fellow inmates would include James B. Stockdale, the highest-ranking U.S. Navy officer held captive in Vietnam and Ross Perot’s vice presidential running mate in his 1992 campaign.

McCain arrived at the Plantation in December 1967, weeks after his own capture, and was thrown from a stretcher onto the floor in Col. Day’s cell, according to an account in Men’s Vogue. “We were the first Americans he had talked to,” Col. Day wrote years later in “Return With Honor,” one of two memoirs. “We were delighted to have him, and he was more than elated to see us.”

“I was stunned by his condition,” Col. Day recalled, according to the Men’s Vogue account. “My first thought was: They dumped him on me so they can claim we let him die. I did not think he would live through the night.”

Along with another prisoner, Col. Day helped nurse McCain back to health. They “wouldn’t let me die,” McCain said Monday on the Senate floor in an emotional tribute to Col. Day. “They bathed me, fed me, nursed me, encouraged me and ordered me back to life.”

In April 1968, Col. Day moved to another prison, a moment that he described as “terribly sad” because it separated him from McCain. They later were reunited at the Hanoi Hilton. There, when armed guards barged in on the inmates during an illegal religious observance, Col. Day led prisoners including Stockdale in singing the national anthem.

Throughout his imprisonment, Col. Day “continued to offer maximum resistance,” according to the citation for the Medal of Honor, given to him by President Gerald R. Ford in 1976, three years after his release. “His personal bravery in the face of deadly enemy pressure was significant in saving the lives of fellow aviators who were still flying against the enemy.”

George Everette Day was born Feb. 24, 1925, in Sioux City, Iowa. He left high school to join the Marine Corps during World War II and served in the Pacific theater. After the war, he received a bachelor’s degree from Morningside College in Sioux City and a law degree from the University of South Dakota.

He later joined the Air Force Reserve and was recalled for active duty during the Korean War. He retired in 1977. He was the subject of a biography, “American Patriot: The Life and Wars of Colonel Bud Day,” by Robert Coram (2007).

After his military career, Col. Day maintained a law practice in Fort Walton Beach, Fla., and worked prominently on cases involving government health care benefits for military veterans. He campaigned for McCain, an Arizona Republican, during his unsuccessful presidential races in 2000 and 2008.

In the 2004 presidential election, Col. Day opposed the candidacy of Sen. John F. Kerry (D-Mass.) and appeared in ads purchased by Swift Vets and POWs for Truth, the association that controversially sought to discredit Kerry’s war record in Vietnam.

Col. Day’s survivors include his wife of 64 years, the former Doris Sorensen, of Shalimar; four children, Steve Day, a captain in the U.S. Merchant Marine, of Gulf Breeze, Fla., retired Air Force Lt. Col. George Day Jr. of Spring, Tex., Sandra Hearn of West Monroe, La., and Sonja LaJeunesse of Fort Walton Beach; and 15 grandchildren.

“Bud showed me how to save my self-respect and honor,” McCain said Monday from the Senate floor, “and that is a debt I can never repay.”