@Richman (I'll be honest, I didn't know last chapter was released so I was confused reading this, but now that I've reread both of them, it makes sense how we got from sensei in her room to here)
I think this actually does imply that the author is the main character's father, given how she seems to exude behaviors similar to Nagi.
It's also implied the mother views as the lynchpin of the family and that if he was gone, she wouldn't have anything left to look forward to with what remains given her other son is bipolar and explosive, her mother is on the verge of death, and she's still prostituting herself to Gen's father to protect Reiji. If Reiji is gone after all she sacrificed, she wouldn't have anything left to live for and so wants him to be the one thing that she can say that she contributed to the world.
It's also interesting how she goes immediately from sadness to anger when she changes the topic and brings up the teacher. I think her experiences with dealing with abuse and sexual predators- if the author is truly the father and if Gen's father is anything to go by- that she can tell if someone is just using you for their own emotional satisfaction. It's clear that the teacher only wants to date Rei because she's desperate to get pregnant and to get married so she can look good in the eyes of her family and society, and that she wants to take advantage of Rei's emotional vulnerability and psychological instability due to the confusion he's going through. The fact his mother hits the nail on the head with detecting that Yuri gave him a key to her house back and is using him indicates she's got a lot of experience with this situation and is much more observant than she's letting on, and probably knows that he's been abused by Gen and that he has been interacting with the author.
That last panel with Yuri's face is very ominous, and I don't like the implications of it.
