What an incredibly cathartic, albeit emotionally charged, experience. I am very happy you were able to make amends with your brother, more importantly that you successfully spoke your mind and felt validated in doing so. Something you said really struck me:
"The paradigm of the time was that it was a moral failing, not a criminal act, and with prayer, repentance and penance, someone could turn his life around. My brother said he really felt that he could help. He believed he had some sort of power to bring about change and through prayer and support Fr Bob could be healed. That mindset existed throughout the hierarchy of the church and at all levels from parish priests to archbishops to cardinals, the belief was that through prayer, penance, and forgiveness, the abuser would stop the evil. When viewed through today’s paradigm, it is dead wrong, but for the time, it made sense."
I think a lot of organizational leaders, family members, and so on and so forth make this mistake in approaching abusers in this manner. (especially ones they know and like or are related to). Their motivations vary but the results are always the same: more self-immolation and more victims.
"Life is like this dark tunnel. You may not always see the light at the end of the tunnel, but if you keep moving, you will come to a better place." ~ General Iroh