How did the grandfather die in Fever 1793?

In "Fever 1793" by Laurie Halse Anderson, Grandfather, who is a key character in the story, dies from complications related to the yellow fever epidemic that ravages Philadelphia. He becomes ill and ultimately succumbs to the disease, highlighting the devastating impact of the epidemic on families and communities during that time. His death serves as a poignant moment for the protagonist, Matilda, as she grApples with loss and the harsh realities of the crisis.