The picture didn't pop up right away, so at first I thought your father was maybe in the Temptations (lol):
Trivia: Although the song is most associated with the Temptations, it was actually first recorded by the Undisputed Truth ("Smiling Faces Sometimes" was their only other hit).
More Trivia: "Just My Imagination" was penned around the same time for the Temptations by their then producer, and Motown legend, Norman Whitfield. The Rolling Stones did a great cover of the tune on their "Some Girls" album over a decade later, bringing this post full circle...
ADG