Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

This past Christmas season, I went to visit my parents. During the visit, I found the letters written by my parents to each other during the war in the attic . The letters were piles high,dirty and had not been touched for decades. I asked Mother and Father if I could take the lettersback to my home. They agreed.As I opened each letter, all of them delicate with age, I discovered a new page in this private part of my parents' lives. My father served in the army. His letters were full of frontline descriptions, and they continued all the way through the battle. Each of my mother's letters was sealed with a lipstick kiss. Father wrote that he sealed his return letters by rekissing her lipstick kiss. How they had been missing each other! I finished reading six months of the letters and discovered there were at least eleven months missing. Maybe they were lost forever. Not long after our Christmas visit, Father became very ill and was in hospital. I went to the hospital to see him. As I sat by his bedside, he told me how much receiving those lipstick-kissed letters had meant to him when he had been so far from home. Later that evening, Mother and I revisited the attic in search of the lost letters. Finally we dug them out of Mother's old college trunk. The next day was Valentine's Day, and we went to the hospital. At my father's bedside, I showed him an old envelope. His curiosity was aroused. When he carefully opened the letter, he recognized it and his eyes were filled with tears. He read the love messages that had been delivered years before to my mother in a quavery voice. This Valentine's Day, we were lucky that we had everything.
How did the author's father feel when he saw the letter in hospital?