Beauty and the Beast!? Dirteng and Joi-san - S6-E37
Continuity mistake: When Nurse Joy walks to the window at the beginning of the episode, her chair is positioned on the second row of tiles from the window while her desk is positioned on that and the first row of tiles from there, but when Ash and friends watch the footage of the shot, Nurse Joy's chair is positioned on the third row of tiles from the window while her desk is positioned on the second and fourth rows of tiles from there. Also, the way Nurse Joy braces when the wind blows changes. (00:04:54)
Answer: He is a good guy but just found himself in a bad situation when he worked for Lysander. He didn't want him to harm Ash and his Pokémon when he was trying to get the special bond between Ash and his Greninja to work. He does leave Lysander and go back to being a good person.