In 1976, when all the eight Jesuit priests still lived, one of the survivors, a German named Father Hubert Schiffer, represented the group with this answer:
We survived because we were living the message of Fatima. We lived and prayed the Rosary daily in that home.
What is the message of Fatima, you ask?
If my father-in-law happens not to be around to address that question, here is the answer from a 2010 Catholic Herald article that goes into much detail about this event.
The essence of the Fatima message concerns conversion from sin and a return to God, and involves reparation for one’s own sins and the sins of others, as well as the offering up of one’s daily sufferings and trials.
There is much theology wrapped up in that answer and even more in the Catholic Herald article offering layers of theological explanations as to why those eight priests miraculously survived and even lived into advanced age.
But here is the quickie 30 second version.
August 6th, the day the bomb fell on Hiroshima, also happens to be when the Catholic Church annually celebrates the Feast of the Transfiguration.
The New Testament tells how Jesus went up to a high mountain and was “transfigured” before his apostles Peter, James and John. The Book of Matthew reads in 17:2 “his face shone like the sun, and his garments became a white as light”. (First hint, similar to what the residents of Hiroshima would have seen seconds after the bomb was dropped.)
Now, fast forward ahead to the 1917 Miracle of Fatima in Portugal, commonly known as the Miracle of the Sun.