"My grandfather told my father, 'Your role is to take care of Andy and make sure he goes to school, because he's going to be successful someday,'" Warhola's son, Donald, told the Pittsburgh Post-Gazette.
After their father's death, John Warhola worked odd jobs to support their mother and pay for the education of his brother, who moved to New York and became Andy Warhol. Warhol died in 1987.
Donald Warhola said his uncle called his father every Sunday to keep up on the family.
"My father … played a pivotal role in helping Andy become what he wanted to become. He did that out of the love of his heart," said Donald Warhola.
Warhola was a board member of the Andy Warhol Foundation and helped establish the Warhol museums in Pittsburgh and the family's ancestral home in Medzilaborce, Slovakia.
"We are losing our own father, our founder," said Michal Bycko of the Slovak museum. "With the sudden departure of John Warhola, our museum is losing its soul."
Warhola is survived by his brother, Paul, and sons, Donald, Mark and Jeffrey.