For those who haven't been following along since the beginning. Mirai has some kind of problem with emotions (I don't know exactly what it is, but it's related to her autism). If I understand correctly, strong emotions shake her, which is why she ends up fainting/having convulsions.
It's no wonder her parents were worried, and they were also happy because Mirai had stopped having convulsions since Hidaka's classes.
I hope it's just some kind of exhaustion due to excess emotions and that they can save her. Let's see what the scriptwriter has in store for us.
PS: I can even tolerate the director's son failing in the games. Aritsu can't. He's just a lot of talk and little action.