Pier Giorgio had one younger sister, Luciana, born on August 18, 1902. The two were very close friends until the day that Pier Giorgio died. On January 24, 1925, Luciana married a Polish nobleman, Jan Gawronski, and moved away from the family. This was a very difficult separation for Pier Giorgio. He described it in a letter he wrote the next day to his best friend Marco Beltramo:
"Yesterday my sister was married with the Rites of the Catholic Church... But while I am happy because my sister is happy the more so because her husband is good in the sense that you and I understand, on the other hand yesterday the separation was terrible. You can imagine my only sister, the companion of my childhood: to see her leaving for such distant shores was for me a stroke in the heart."
Just a few months later, however, toward the end of June, Luciana returned home to be with the family during her grandmother's final illness. The funeral of Linda Ametis was held on July 3. The very next day, Pier Giorgio died.
Luciana and her husband had six children, four daughters and two sons. For some time, they lived abroad. However, during Hitler's reign they returned to Italy. Luciana became very involved in Pier Giorgio's cause for canonization and is the author of several books about him. Two have already been translated into English: "A Man of the Beatitudes: Pier Giorgio Frassati" and "My Brother Pier Giorgio: His Last Days." She was the original editor of the book of Pier Giorgio's letters that was published in the U.S. in 2009. Luciana Frassati also authored
several other books including books of poetry, the history of Turin, and a detailed biography of her father Senator Alfredo Frassati.
Luciana died at the family villa in Pollone on October 7, 2007. She was 105 years old. All of her children are living. Her daughter, Wanda Gawronska, continues to maintain the Associazione Pier Giorgio Frassati in Rome.
The funeral of Luciana Frassati took place on October 9, 2007. A Mass of Christian Burial was celebrated in the morning in Turin and another later in the afternoon in Pollone. Her remains were interred in the Pollone Cemetery in the exact spot which held Pier Giorgio's remains until 1990.