Elizabeth Warren’s oldest brother died of coronavirus on Tuesday night in Oklahoma, three weeks after testing positive for the virus, the former presidential candidate said on Twitter on Thursday.

Donald Reed Herring, 86, was admitted to intensive care on April 15 and died six days later, according to the Boston Globe. He was not on a ventilator.

“I’m grateful to the nurses and 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 — and no funeral for those of us who loved him to hold each other close,” Warren wrote on Twitter, posting an old photo of her siblings. “I’ll miss you dearly my brother.”

Herring joined the Air Force at 19 and spent his career in the military, including five and a half years off and on in combat in Vietnam, Warren said. On the campaign trail, the Massachusetts senator spoke frequently about her three older brothers to inform voters about her conservative upbringing, emphasizing her siblings’ military background and Republican politics.

So far, about 45,000 people have died from coronavirus in the U.S.