The last post is probably the best take on this subject.
One of the most difficult aspects of being a member of The Holy Mother Church is acknowledging that we have had members, and leaders, who have been less than faithful to the Teachings of the Church. There will always, therefore, be historical facts about actions taken that were less than admirable. To deny them is foolish - HOWEVER, to use those facts as a reason to declare that the Church has not authority, or is not the Church founded by Jesus Christ Himself is foolish and dangerous.
There were also members of the clergy, at the Vatican, who were active in hiding Jews and Partisans during WWII. This historical fact cannot be denied any more than the facts of members of the clergy that did NOT behave according to the teachings of Christ and His Bride.
History is a two-edged sword. It can swing both ways, and one must be careful when using it as a weapon. My response to your friend would be, “I have no doubt that some of our members did not act according to the teachings of Christ during WWII. I would have to see concrete proof that the POLICY OF THE HOLY ROMAN SEE was to help Nazi War Criminials to escape. Do you have such proof?”
The United States unwittingly helped Nazi War Criminals escape punishment after the War. Many European Nations looked the other way during the aftermath of the War and let people slip through their fingers - they had a huge mess to clean up. Was it their official policy or was it the actions taken by a few?
In the United States we have a trial in the South taking place in which a Baptist Preacher is accused of being one of the people who threw a bomb into a Church that killed little Black children during the civil rights movement. It would never occur to me to condemn the Southern Baptish Church for the actions taken by this man, or by so many other Southern Baptists in regards to lynchings, rapes and murders of Blacks, Jews and others in America after the Civil War. That would be wrong.