Don Reed Herring (center), along with Elizabeth Warren's other brothers, David Herring (left) and John Herring, in a video released by her presidential campaign in January. Screen capture

Donald Reed Herring, the oldest brother of Senator Elizabeth Warren, died on Tuesday night in Norman, Okla., about three weeks after testing positive for the coronavirus.

Herring, a 20-year veteran of the US Air Force, was 86.

Warren, who has been a vocal critic of the Trump administration’s halting response to the pandemic for months, has not previously revealed that her family was waging its own personal battle against the virus. She confirmed his death in a statement provided to the Globe and said the cause was the coronavirus.

“I’m grateful to the nurses and other front-line staff who took care of my brother, but it is hard to know that there was no family to hold his hand or to say ‘I love you’ one more time. And now there’s no funeral for those of us who loved him to hold each other close,” Warren said. “I will miss my brother.”

Elizabeth Warren’s brothers were a silent fixture of her campaign

Herring was born in 1933 and attended the University of Oklahoma, but did not graduate, before enlisting in the Air Force, where he flew B-47 and B-52 bombers. He flew 288 combat missions in Vietnam, eventually becoming a B-52 squadron pilot and a squadron aircraft commander. He earned numerous decorations before retiring in 1973 as a lieutenant colonel and starting an auto-detailing business. In her statement, Warren described Herring as a natural leader with a quick, crooked smile.

Known as Don Reed, Herring was the oldest of Warren’s three brothers, and he leaves the other two, John Herring and David Herring. The trio became a silent fixture of their sister’s presidential campaign, because she spoke often of them as a link to her upbringing in a more conservative world, highlighting their military service and the fact that two of them — Don Reed and David — were Republicans who agreed with her on some fundamentals. They never spoke to the press, but all three appeared in video footage used by her campaign.

From left: Don Reed Herring, Elizabeth Warren, John Herring, David Herring. Family photo

Don Reed Herring lived with his wife, Judith Anne Hart, in Newcastle, Okla., before his death, in a small house amid wide fields. According to information provided by his family, he had been diagnosed with cancer years ago and undergone treatment, and was hospitalized for pneumonia in February. He then moved to a rehabilitation center to recover. The family did not identify the center.

The coronavirus has posed a particular risk to people at inpatient care facilities. Other patients in the facility where Herring was staying had active cases, according to what the family was told, and he was tested for the virus in early April. He received a positive result the next day, but did not show symptoms of the virus for another 11 days.

Donald Reed Herring, the oldest brother of Elizabeth Warren. Family photo

Herring was moved to intensive care at Norman Regional Hospital on April 15 and died six days later. He was not on a ventilator.

The coronavirus has separated people around the country from loved ones fighting the illness, and that was no different for Warren’s family. Herring’s wife was unable to visit him in recent weeks. Warren spoke with him daily before he was transferred to the hospital, but that became more difficult to do as he grew sicker. She last spoke with him on Sunday, when he seemed to be doing better.

In addition to his siblings and his wife, Herring leaves his two sons, John and Jeffrey. His first wife, Nancy McKelvain, died in 1982 of leukemia after the two were married for about 27 years.

Herring was 16 years older than Warren, and she was a toddler when he joined the military at the age of 19.