It was Bishop Sheen that was quoted as saying that Rome and Mecca would be united via their common worship of Mary. Are you referring to this?
Since nothing ever happens out of heaven except with a finesse of all details, I believe that the Blessed Virgin chose to be known as "Our Lady of Fatima" as a pledge and a sign of hope to the Moslem people, and as an assurance that they, who show her so much respect, will one day accept her Divine Son, too.
It isn't the worship of Mary Bishop Sheen was referring to, it was the worship of her Divine Son.