Matilda's Grandfather is a solider, Captain William Farnsworth Cook of the Pennsylvania Fifth Regiment. He served under George Washington. He has a pet parrot named King George that he won in a card game. He's one of Matilda's most crucial mentors in the novel – the two are very close.
Grandfather is a symbol of an earlier time since, as he reminds us over and over, he was a soldier in the Revolutionary War. He's a representative of an older generation that passes down their skills, history, and knowledge to the youngsters. Much of what Matilda knows of the world, after all, she has learned from her grandfather. He teaches her the fundamentals of soldiering, which, believe it or not, actually come in handy when stranded in the country (Chapter 8). Matilda will also wield his battle sword during the burglar attack and later uses it to defend the children in the coffeehouse.
Grandfather's death is the one that hits closest to home for Matilda. By losing someone so dear to her, Mattie truly experiences the intense feelings of pain and loss that death can bring. How does she, in the end, choose to remember her grandfather?