Popocco! Grass Pokémon Battle!! - S4-E21
Continuity mistake: When Ash and friends admire the plants in the corner, there is no pot between the two right pots on the bottom shelf of the shelving unit adjacent to the background, but in the last shot inside Ephraim's house, a pot with a plant appears. (00:05:16)
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.