As much as it is admirable that Momoko has taken care of the child. Her background to support the child is just a shitshow with no stable houshold at all. Living together with a brother an abscent mom and no father around who would "normally" generate the income. Taking care and not handing the issue over to officials is plain wrong.
The Kanzaki sensei dude is correct, that "whatever" is going on is over the head of Momoko. Seriously she should be out there with her friends, experience to grow up and do her studies to become a mother when the time is right. This has become a more or less permanent situation. And this is plain wrong.
Beside the fucked up teacher x student side story that produced the happening in the first place.