Miss Pergrine's Home For Peculiar Children - Chapter 4. Why is grandpa portman considered a hero on the island? How does Jacob's emotions toward him alter/change?

Oggie adds that everyone in the Home was killed - everyone, that is, except one sixteen year old boy. Jacob reveals that that must have been his grandfather and leaves, his two listeners shocked and surprised. Back at The Priest's Hole, Jacob updates his father, suggesting that the trauma Grandpa suffered might have explained why he was such a poor father. As he goes to bed, Jacob wonders how it's possible that Miss Peregrine, who was apparently killed in the bombing, wrote a letter to his grandfather fifteen years after she died.