Why doesn't he just leave the job? Or maybe he is just to old to jump to another job? He is only 40 yrs old. Ppl like him at that age is considered to be experienced employee?
I'm 29 and I have been working at the same place since I graduated from college.
And I have lots of reasons to not change jobs now.
For once, it's a culture thing with Japanese where the more you change jobs, the harder people would accept you in since well, it seems like you would leave soon after all. On the other hand, if you worked for a place for a long time to then change jobs, they would think something happened and might get suspicious of your, thus, the chance of getting in abysmally lowers.
Another is that, well, after working at the same place for so long, it's hard to work up the courage as well as the motivation to change jobs, even if it's shitty. Like, you just get too lazy to change jobs anymore. Changing it even once mean you have to get used to the place, make new acquaintances with other people at the new place, get youself used to the work style, flow and customs, etc.
In other words, it's not uncommon, especially in Japan.
And this is just me speaking from my own experience.