Elmer's Dad is a minor character who briefly appears in a few episodes. He almost always appears in group shots with other parents, and not much else is known about him since he has never been the focus of any scene.
Like his son, Elmer's dad has a huge boil on his face and wears thick framed glasses. Other than this, nothing is known about him. He has never spoken out of unison with other characters, and therefor does not even have an assigned voice actor.