What does the stranger ask Winnie and her grandmother?

In the story "Tuck Everlasting," the stranger, who is actually a man in a yellow suit, asks Winnie and her grandmother about the whereabouts of the Tuck family. He is particularly interested in finding the Tucks to learn more about their mysterious secret, which he believes involves a magical spring that grants immortality. His inquiries raise suspicions and hint at his ulterior motives regarding the Tucks and their secret.