Cardinal failed as a human being
Madam -- In accepting that Cardinal Brady was not influential in terms of the Catholic Church at the time of the 1975 inquiry into abuse, anyone can become influential on a human level. Cardinal Sean Brady was aware of the abuse of the 14-year-old boy in question and although he carried out his 'religious' duties, he failed the boy and other abuse victims.
Excuses have been offered for the cardinal regarding his ranking in the Church, but he was a man as well as a priest. If any member of society comes into receipt of such information regarding abuse, clerical or not, they can then become the voice of influence.
I would go as far as to say Cardinal Brady should resign because of his conduct as a man, and not in his capacity as a priest. His silence at the time showed blind ignorance to his moral duties as a human. He does not now possess one ounce of credibility.