YA Fantasy with a School and a Evil Scientist who turned his Henchmen into Photosynthesizing Fishmen

[Muhammad]

So there is a book I read maybe 3-4 years ago. It's a book series where the main character is in a secret school for reasons I can't remember. There was an evil scientist who was like half ape or something and was immortal and intelligent while wearing his lab coat. The moment he took it off, he turned into a giant monkey and was incredibly strong. There was also a pirate or something that was the main characters relative who had the same thing as the scientist only the piece of clothing was implanted into his heart. The scientist also genetically modified his henchman to be able to photosynthesize and gave them gills.