@ Ryomi
Okay we can all agree that the daughter is a bitch, but she has a point. Her father is dating (and for all she knows might as well fucking) her best friend, a girl of her age. That hits hard.
That's the thing, he was NOT dating her (but he will soon probably, why should he reject her now ?), he even rejected her, even if he was tempted, with how shit his life is now.
Hell, Koto even said it to his daughter "he don't like me, it's only me who chase him".
Sorry, but even if she is a teenager, his daughter is horrible, she has no excuse.
Even if the death of a loved person hurt a lot (i know that feeling) , you should be careful and help the rest of your family, not make their life even worse.
If the MC didn't had Koto, he would have just killed himself after this chapter, and his daughter would regret it for all her life.