ok this is kinda dark so just a warning for abuse/ sexual abuse
so basically i think since natsuki wears clothes where you can see her arms/ legs in the event where your in her house, I don't think her dad physically abuses her because you can see no bruises and i dont think thats something that the game devs would just forget. i think she was actually sexually abused. i also think that in natsukis secret poem when she says ' i like when papa doesnt comment on my friends' i think she meant comment in a sexual way as natsuki is probably the same age as the majority of her friends so she doesnt like it when he says does things
anyway just my theory lol (also i realised how much i said i think lmaoo)