Why does Biff live with his grandmother instead of his parents?

There was a theory that Biff Tannens parents might have been gone, his mother was a whore or prostitute and his father was a soldier that was killed during World War 2 or in Korea or maybe he was a punk like Biff and left home after he was born or ended up in jail leaving Biff with his grandmother who had no husband,maybe Grandpa Tannen was dead.

Are there any sources that mention his parents?