I want to know the answer to the following question:
Who sent him the letter informing him of his mother's death?
All the background I'm provided with is that "He was sent a letter by Cardinal Eugenio Pacelli, and Roncalli later recalled that it was probably the last letter Pacelli sent until his election as Pope Pius XII on 2 March 1939.". Is that enough to answer the question?
Answer: yes