So the father knew that it was at that hour in which Jesus said to him, "Your son lives." He believed, as did his whole house.
He's asking Jesus to go from Cana down to Capernaum, twenty miles, to heal his son. Of course, if you've got a son that's dying and you're the dad, you're going to be desperate. You're going to do your best if you feel that, "Here's a man that can help my dying son."