Bro tf someone pls explain ch 2?? I swear im dumb asf

What I got was that one of the mother's client was raping the brother and the returned the brother to water (drowning him in the tank) because he had become an anemone (anemones are used as a refuge for fishs to hide). He even says "I was trying to help him", I think that's way he drowned his brother and trowed the body in the ocean. His brother was abusing him sexually for a long time (he says in the beginning that his brother was obsessed with him and he was scared), both of them were twisted as fuck. Later on it's just him hallucinating for guilty and messed up feelings I guess