Massachusetts Democratic Sen. and former presidential candidate Elizabeth Warren confirmed reports Thursday that her oldest brother has died of complications caused by COVID-19.

The Boston Globe reported that Donald Reed Herring, who was 86, died Tuesday night in Warren's home state of Oklahoma. Herring was an Air Force veteran who flew B-47 and B-52 bombers and flew more than 200 combat missions in Vietnam, and eventually became a squadron aircraft commander. He retired from the Air Force in 1973 as a lieutenant colonel, and then started an auto detailing business.

Warren had not previously revealed that her brother was fighting the coronavirus. Before ending her presidential campaign, Warren frequently referred to Herring, along with her other two brothers, on the campaign trail.

According to the Globe, Herring was initially hospitalized in February for pneumonia and was then transferred to a rehabilitation facility to recover. When it was determined that other patients in the facility had tested positive for COVID-19, Herring was tested in April and ultimately was determined to be positive, although he did not begin to show symptoms for 11 days after the positive test. He was ultimately moved to intensive care at Norman Regional Hospital on April 15, and passed away Tuesday.

In her statement to the Globe, Warren lamented in particular her inability to be by her brother's side as he passed due to restrictions on visitation caused by the coronavirus.

"It is hard to know that there was no family to hold his hand or to say 'I love you' one more time," she said. "And now there's no funeral for those of us who loved him to hold him close. I will miss my brother."

