Interesting choice of words from Hiiragi in she "didn't" have a good parent, not "doesn't." Which ties into my theory that Hiiragi's mom is probably gone/deceased and she now lives alone.
Also I want to shake Tomikawa and shout at her YOUR MOTHER IS PROVIDING THE MINIMUM LEGAL SUPPORT DEMANDED OF HER BY THE JUSTICE SYSTEM, YOU DESERVE BETTER THAN TO BE HER DOORMAT.
Poor girl has been so conditioned by her mom to think that being not kicked out onto the street is an act of love and kindness.