Busch's death left the NASCAR world grieving the loss of one of the sport's all-time greats, just days after he won his final race.

With a week to process Busch's death, it's become clear what a sizable loss this is for NASCAR and its future.

Kyle Busch, who passed away at 41 due to pneumonia and sepsis, was not in good form, according to Brad Keselowski.

Kyle Busch, 41, died on May 21 after being rushed to the hospital when he was found unresponsive inside a race simulator near Charlotte, North Carolina.

Kyle Busch's death certificate reveals new details about the sudden passing of the NASCAR icon.

Busch's death left the NASCAR world grieving the loss of one of the sport's all-time greats, just days after he won his final race.