NASCAR legend Kyle Busch was ill for “weeks” before he passed away from sepsis on May 21, according to his death certificate released on Wednesday. The 41-year-old died 24 hours after being rushed to the hospital, and had suffered from bacterial pneumonia “of an undetermined etiology” for “days to weeks” before he passed. 

The severe bilateral pneumonia progressed into sepsis, causing disseminated intravascular coagulation (blood clots forming in the bloodstream that block vital blood flow to organs), followed by hemorrhagic shock. A 911 call on May 20 revealed that Kyle was struggling to breathe and had been coughing up blood before he was rushed to the hospital in Charlotte, North Carolina. 

“I’ve got an individual that’s [got] shortness of breath, very hot, thinks he’s going to pass out, and he’s producing a little bit of blood, coughing up some blood,” said the caller. “He is awake. He’s awake on the bathroom floor right now.”

Kyle had been suffering from a sinus cold at what was to be his last ever NASCAR race on May 10 at Watkins Glen International. The broadcaster shared that the G-forces and elevation changes that came with racing had exacerbated his illness. 

The father of two’s longtime rival, Brad Keselowski, told People he ran into Kyle on a flight just a week before his passing and noticed significant changes. 

“Kyle is normally a fairly gregarious person, very outgoing – and he wasn’t,” Brad said. “He sat down one row behind me and next to me and fell asleep right away, and I could tell he wasn’t feeling well.”

NASCAR CEO Steve O’Donnell led a moment of silence for Kyle at the Coca-Cola 600 weekend in Charlotte. “Every racetrack was Kyle Busch’s home. He competed like he had something to prove every single race, when in reality he had already proven everything,” Steve shared.  

“What I think we’ll miss the most isn’t the wins. It’s the guy who quietly wanted to help a teammate, give some advice, the husband, the father, the guy who quietly did things for others when no one was watching.”

Kyle is survived by his wife, Samantha, his 11-year-old son Brexton, and his four-year-old daughter Lennix. “Samantha, I want you to know that this sport stands with you, and you and your children are NASCAR family forever,” Steve added. 

“Brexton and Lennix, your dad loves you with all his heart. Everyone gathered here, everyone behind you, everyone watching on TV and all those people up in that grandstand, they are your family, and we’ve got you.”

“Kyle Busch lived just about every chapter of what you could do in NASCAR,” he later said in a press conference, before describing the athlete as fierce and competitive. Denny Hamlin, Kyle’s former teammate, shared a touching tribute on social media. “Absolutely cannot comprehend this news,” he wrote. “We just need to think of his family during this time. We love you KB.”