It might help if you included you grandmother's name or any other clues as to the grandfathers that you might have.
Parents names, aprox birth year and location, if available, sometimes those clues lead to more information. Is your father Jr?
Could be this man b. abt 1889 in Michigan but death would have been after 1930.
U S Census, 1930 Pittsburgh (Districts 1-250), Allegheny, PA
head Willian Dahlman M 41 Mich
wife Anna L Dahlman F 41 PA
son William Dahlman M 10 PA
dau Virginia Theakften F 18 PA
son-in-law Louis G Theakften M 22 PA
US Census, 1940 Ward 15, Pittsburgh, Pittsburgh City, Allegheny, PA
head Anna Dahlman F 51 PA widow
son William Dahlman M 20 PA
dau Virginia Theakston F 28 PA
Pennsylvania, County Marriages
W Earl Bothwell
age: 46 est birth year: 1895
father: William mother: Matilda Bertsche
Marriage 01 Aug 1941 Allegheny, PA
spouse Virginia Dahlman
age: 29 est birth year: 1912
father: William mother: Anna Kapenos
Pennsylvania, Births
Anna Louise Kapinos Female
Birth 25 Mar 1889 Pittsburgh, Allegheny, PA
father Andrew Kapinos mother Augusta Gibloski
U S Census, 1910 Elizabeth, Allegheny, PA
self William Dahlman M 21y Mich/SWE/SWE
wife Anna Dahlman F 20y PA/GER/GER