I would suggest that he "confessed" as a gift to his son, who has been milking it ever since. The photograph, one of the three "tramps," in my opinion, cannot possibly be him because he was too young at the time to have been that person. Also, he always denied that it was him in the photo, and he didn't change his story at his "deathbed confession," not that I would believe a word he said. He was already a convicted criminal in the Watergate scandal, so there wasn't much of a reputation to protect.
RE: Why MIT's Orwellian "Largest-Ever Study of Fake News" Is Nonsense.