First and only time Angela's father---Robert Robinson---and Mona's former husband, is ever seen. He was played by Efrem Zimbalist Jr..
Fran Drescher closely copied this sitcom. She named one of her relatives "Mona" and then hired Efrem Zimbalist Jr. for Material Fran (1994), for no other reason than because he had appeared here, and so she had to have him too.
Dr. Anderson said that Mona was healthy enough to live to be 100. Ultimately, Katherine Helmond would live to be 89.