In the advertisement, anyone with information on the disappearance was asked to message 646-450-6530 or 1-800-litigate.
Gale, one of the animal sanctuary owner's daughters, said: "We are a real family and to us, he was daddy."
The family are currently offering a $100,000 for information about his whereabouts.
Donna, another of his daughters, explained in the ad: "I'm Donna. I'm Don Lewis' oldest daughter. We need to know what happened to our father."
The family's attorney also referenced the speculation about Carole.
He said: "Don Lewis mysteriously disappeared in 1997. His family deserves answers, they deserve justice. Do you know who did this or if Carole Baskin was involved?"
The story of Carole, 59, and Don came to worldwide attention through Netflix's hit documentary series 'Tiger King', which was released earlier this year.
Don disappeared in August 1997, when his van was found abandoned at an airport.
It's been suggested he was planning to fly to Costa Rica, but police haven't found any evidence that he ever left the US.
In April, Hillsborough County Sheriff Chad Chronister confirmed Carole is not a suspect in his disappearance.
He said: "We don't have any evidence to even call her a person of interest."