Haruki hears about Kazusa's moving from her mother, who she hadn't been on good terms with.  He feels betrayed and angrily confronts her.  But his words force open the door to Kazusa's heart, which she had desperately tried to keep closed so that the three of them could stay together.
I can't believe the school 
doesn't say anything to her.
Ich kann echt nicht fassen,
dass die Schule diesbezüglich nichts zu ihr sagt.
No puedo creer que la escuela no diga nada.
No me puedo creer que 
el instituto no diga nada.
Não acredito que o colégio 
não diga nada para ela.