Father Joe talks about Lucia, who's entire life was one of suffering and offering, as she made the redemptive sacrifice that was asked of all the visionaries. Lucia accepted God's plan for her, as we all should.
The Fatima visionaries were given a vision of hell that made a tremendous impression upon them.
Write that by day and by night My gaze is fixed upon him and I permit these adversities in order to increase his merit.
God was preparing Lucia before the visions took place. Father Joe notes that Lucia's mother urged her to ask God to make her a saint, and Lucia made a self-offering.