What a nice chapter. Kids here will be, and are, alright.
...Then the sudden author condition scare. That must have sucked, hope all is well for him.
Real talk though: I know Japan in particular have pretty heavily seasoned foods. And that usually means a lot of salt with the number of sauces they use for everything. This average diet is what contributes to them specifically having more of a specific type of disease. I think it's cancer likelihood of that area, but I don't recall specifics I read about that.
Author should cut back on salt levels to start, and sip water more regularly. And if already doing that, go pee more.
This might mean needing to (his wife?) prep own food more, to have some favorite dishes with more controlled levels of seasoning/salt in particular.
General advice from having recently been around someone experiencing the same condition.