This man is the husband of Wyatt's Mother. He is the father of Wyatt and father-in-law of Susan. He is the paternal grandfather of Penny, Randall, as well as Penny and Randall's Sister. He is the ex-paternal grandfather-in-law of Zack Johnson and the current paternal grandfather-in-law of Leonard Hofstadter and Penny and Randall's Brother-in-law (Sister's Husband). He is a great-grandfather to Penny's nephew. Penny and Randall's Cousin may be his possible grandson.
He is indirectly mentioned after Professor Proton asks Penny if she has any single grandmothers and she answers that they are both married.