Responses
Oh I didnt catch the affair part.. I just thought he was like a step-son and adopted to the family
But yeah out of all the stories this one was messy one and couldnt really tell which part was dream and what wasnt
For everyone freaking out about Chpt 4, it goes like this: Kyouko (Neesan) is the first child of her father and his first wife (who I'm assuming died), father remarries, his second wife has a affair and produces Harumi, who is completely unrelated to both his "sister" and "father" (he literally says this at one point lol).
It's obviously still fucked up that these two (essentially) step-siblings would have sex, so Kyouko's father married her off quickly to the MC just to save face and disowns the bastard son (that again, is 100% not related to him anyway, but it seems this fact is still being kept quiet).
Hope that makes more sense now :)