Based on the text in Chapter 10 of the book, how are some of the townspeople aware that Penny's late grandfather Falucci had buried cash somewhere on his property?

Based on the text in Chapter 10 of the book, Penny's Uncle Sally (Salvatore) is aware that her late grandfather Falucci had buried cash somewhere on his property, based on a story that had been told to him by old man Garboella.