Lorraine, whom he had always understood to be his other sister, was revealed to be his aunt — June’s sister, Ethel May’s other daughter, the person who had held the secret long enough to be the one to confirm it when it finally emerged.
These three shifts — grandmother/mother, mother/sister, aunt/sister — restructured the basic family tree. They did not restructure the experience. The childhood was the same. The relationships as lived were the same. Only the biological labels were different.
Nicholson has said, in various ways and in various interviews across the years, that he came to think of June as his “sister-mother” — a compound term that tried to hold both the experienced relationship and the biological one simultaneously. That hyphenated term is revealing. It suggests that he was not trying to fully replace one category with the other, to simply say “June was my mother” and drop the “sister” part. He was trying to maintain both the relationship he had actually experienced and the biological truth he had learned. The hyphenation is a refusal of a clean substitution.
The question of his biological father remained, after 1974, genuinely unresolved. This is an important aspect of the story that is sometimes collapsed in the telling: the revelation about June and Ethel May was a single clear answer to a question (who is my biological mother?). The question of biological paternity was not answered with the same clarity.
Donald Furcillo, the Italian-American showman who had married June in 1936 — a marriage that may have been technically bigamous given his prior marriage — later claimed to be Jack’s biological father. He was born in 1909 and died in 1997, long-lived enough that he was alive when the revelation became public. He made no secret of his claimed relationship.