His Grandfather Was a Treasure Hunter and Avid Sailor
While he was tidying up, EvilEnglish started thinking about his grandfather, who had passed away. Once upon a time, he was a sailor who was being pursued by pirates. His grandparents even used to like reading Treasure Island to EvilEnglish.
He linked the home and its hidden treasures with the book’s protagonist’s adventures. It’s hardly surprising that EvilEnglish assumed his grandparents hid valuables somewhere in their home. The key was right there; he only needed to locate it.