I do find these characters interesting.
I get the impression that Haru's stepfather is sexually abusing her, or abusing her to some extent, though that is just speculation and more inline with how she says she's a prostitute, even if she outright rejects all offers we see coming to her that aren't from MC.
The mother seems possessive, but also neglectful and very self-centered. She's living outside of her means and tries to blame a lot of it on her soon, and so she tries to keep him firmly in her hand.
While that's not entirely the impression I got, I can see where you're coming from. What I find interesting is that she seems to be neglecting him quite a bit. I definitely thought that the whole reason he went to Haru to begin with was because he lacked any proper relationships with anyone, and he lacked any positive role models, female or otherwise, in his life. Hell, I'd argue he didn't even have much positive skinship before this point, so just being touched by someone in a way that didn't seem harmful would be better than nothing.
@ninjazz
The character I'm most interested in is actually Yuri because of the way she's been developed. Ironically, she's the foil to Haru in the fact that she accepts everything being given to her and feels entitled to it where Haru feels she has to earn everything she has. She also contrasts MC in this, and so she feels entitled to have other people and to be with them, so when she doesn't feel like MC is with her, and that she deserves him, she gets outraged because she can't process why someone who everyone regards as inferior doesn't want to be and isn't allowed to be with her, especially in favor of someone she thinks is lower than trash.
This manga does do a good job of establishing characters and motivations, as well as making each character complicated in their own right. (Damn, it's good.)