Why the kids never told him they want their appa and want to spend time with him? He would definitely grant their wish. He left because he believed they didn't need him, like all these past years.
Ive thought about the island tho! Its ok then. Let Darryl be there forever. He’s finally found his peace.
Xhemin, u n the kiddos go n chase Darryl ! Now or never! U both n ur small family belongs to the island . pls come back !