From Bulbapedia, the community-driven Pokémon encyclopedia.
(Japanese: マイル Mile) is a recurring character of the Pokémon anime and the former Gym Leader of the Mistralton Gym.
In the anime
Mile first appeared in BW067 after Ash and his friends had just met Skyla. Like Ash and Cilan, he did not agree with how his granddaughter Skyla ran the Gym. He also serves as the Gym assistant.
Mile will appear in BW068 and BW069.
He is similar to Flannery's grandfather in that both disapprove of the way their granndaughter carries on being a Gym Leader of a gym they were previously the leader of.
In the games
It is mentioned that Skyla has a grandfather in the games as well but he was left nameless. It was said that he was once a great pilot.