Early in the movie, Kayoko's family overhear her friend and neighbour Yoshisuke and his mother having to deal with his father being drunk and abusive to them. We never see any of this abuse firsthand but one dreads to think. It's easy to say Yoshisuke's mother bares the brunt of it since Yoshisuke never appears to have any visible injuries though it is possible his father only injures him in areas of the body that can easily be covered by clothing.
At one point in the movie, Yoshisuke tells Kayoko that when he grows up, he's going to earn enough money to buy his father all the sake he can drink. He does this when Kayoko catches him in the act of trying to run away with his infant sibling. Yoshisuke is basically running away because he feels he and his sibling are no longer safe at home and this is before Japan has even gone to War.
Worse still, this could be interpreted as Yoshisuke wishing for his father to drink himself to death.
Just how strong is Kisaburo? We don't actually see it happen but he managed to beat up another boy enough to break the kid's arm and put his remaining limbs and head in plaster just because he caught him and two other boys bullying and upsetting Kayoko. Not to mention he had a stick on his person when he came to his sister's aid. One dreads to think just how much of a No-Holds-Barred Beatdown is Kisaburo capable of dishing out?
One can only imagine what happened to Kayoko's family in Kisaburo's flashback. We don't see the rest of the family after Kisaburo manages to find his way into the local middle school and take cover. For all he and the audience knows, they could have either burned to death, died from smoke inhalation or were crushed to death by other people desperately trying to find cover.
