He's a man in mid life, and he is a half bald man, with a small mustache, hair strand like Lynn Sr., light brown hair, and eyebags. He wears a dark blue t-shirt.
Billy's father appears in "Two Boys and a Baby", when Lincoln and Clyde return Billy to him, who they accidentally took instead of Lily. He returns Lily to the boys, who he had mistaken for Billy and takes his son back. He was frustrated when he realized he took the wrong baby.