It would seem that the brothers, through entirely different methods, had stumbled onto a portion of the truth of the secret island. One had found the means by which what came to be known as Midlanders came to the island, many moons ago. The other had tapped into a power most prodigious, even if he cannot use it consciously.
Still, that left him with another letter to write, and one of the most difficult. He'd call for a Postmoogle, telling him of his progress with the unnamed package and just how far removed from the objective of package delivery he now was. In addition, he'd have this letter for him, a dangerous journey off Eorzea that they undertook for him, in exchange for some of the tougher letters delivered. After all, no one wants their pom chomped.
He re-read the letter, to ensure it was as understandable as possible.
That seems to be in order. With a friendly "Kupo!", the postmoogle went on its way with the sealed letter.