@ninjazz @BZo1480 teacher is just that gullible. He thought Fumi was some kind of hideous looking old hag straight up taken from a dark and edgy episode of the 1998-2002 darkest seasons of Mujer... Casos de la Vida Real, but seeing Fumi being calm and actually pretty looking only made him take the bait.
Ngl, that shit happens a lot irl. People won't get suspucious and will dish aside the issue if the abuser is neat looking and can put a facade of politeness and civility around strangers.
That doesn't mean he couldn't open his eyes if Souta's absence gets prolonged too much. He will blame himself for being too naive.
@SleepyAbra Souta has haru's gmail (i think she handed him her address after the aquarium date). I'm starting to be sure he will have a hand on Fumi's smartphone and give a try to a SOS message. The risk on this is that Souta could run over Fumi's contact list, find out her job as a whore and might snap for sure. If Haru realizes Souta's issues are worse than she thought, then i think she could actually have an emotional breakdown (she almost broke down after realizing Souta's poverty. If she realizes he is subject of multidimensional abuse, both from peers and family, she can easily break down in tears) and will use her stepdad's money and buy him a smartphone.
The other high risk is Fumi realizing there's a strange contact she didn't add on her phone and will get suspicious. If she assumes Haru is the rumored whore, then, in an uber hypocrite move, she could rat her out to the cops and destroy her life only because she is making Souta drifting apart from her.