After testing positive for the coronavirus earlier this month, Donald Reed Herring, the oldest brother of Sen. Elizabeth Warren, died on Tuesday night in Norman, Oklahoma.

In a statement provided to the Boston Globe, Warren confirmed his death and said the cause of his passing was the novel coronavirus.

Herring, 86, was a 20-year U.S. Air Force veteran. On Twitter, Warren praised both the healthcare workers who cared for him and the legacy her brother left. 

“I’m grateful to the nurses and other frontline staff who took care of him, but it's hard to know that there was no family to hold his hand or to say ‘I love you’ one more time—no funeral for those of us who loved him to hold each other close,” she said. “I'll miss you dearly my brother.”

Herring was known for his charm, humor and natural leadership, and Warren said it was his crooked smile that she’ll miss the most about him. 

Herring was born in 1933 and attended the University of Oklahoma. Although he didn’t graduate college, he enlisted in the Air Force and flew B-47 and B-52 bombers. Herring flew more than 280 combat missions in Vietnam and eventually became a squadron aircraft commander. He ended his military career as a lieutenant colonel and earned many other military decorations before retiring in 1973 and starting an auto detailing business.