How does Truman's family try to prove to Truman's that he has left the island before?

Truman's family attempts to convince him that he has left the island before by fabricating stories about past trips and experiences. They claim he traveled to places like Fiji, using vague details to create doubt in his mind. Additionally, they rely on emotional manipulation, suggesting that his memories are flawed or fabricated. Their goal is to maintain the illusion of his controlled environment and prevent him from questioning the reality of his life.