So, the mother of the twins is the blonde woman ( same eyes too ) which also knows one their classmates without her knowing who she is.
Imagine her going to parent meeting impersonating himawari mom just to meet her daughters and his ex in front of her, it would be a mess.
Wondering why their dad categorically refused to let her see the third daughter.
Also the panel of the teacher were dark but credible and grounded to the reality of common peapole who can face such harsh times ( a dad in prison + parent dying ) .