Burt was Linda's maternal grandfather. He passed away before his great-grandchildren were born.
In "The Quirkducers", Linda finds a potato which bears a striking resemblance to him. He appears in a photograph Linda shows to Teddy.
He was Gloria's father and Al's father-in-law. Linda and Gayle are his granddaughters, Bob is his grandson-in-law and Tina, Gene, and Louise are his great-grandchildren.
The photograph Linda shows Teddy of a young her with Burt
The potato that Linda finds that resembles Burt