If you never experienced it first hand, you'd have trouble even understanding the scale of "shame" that society puts into you.
My time there was basically learning that "if you are not sure of something, better apologize in advance". Even being grateful for something is in a way an apology/humility festival. For me it's a better alternative to the typical american bragging and cult of positivity but it's still far from healthy.
The only redeeming quality of that work culture is that, unlike the modern mainland Chinese, Japanese tend to be very perfection driven so they scam you on a much lesser scale...but that makes a lot of stuff a bother to deal with since they will always be looking for potential reworks and be unhappy with the results. This is also an explanation for those that wonder why Inui drops his projects - he has this sudden "Japanese Perfection" idea and tries to do things "better".
I honestly don't know what to tell you other than "don't put any weird ideas in his head" because he WILL see it as a form of criticism to his current work (a different idea means my idea is bad) and might restart shit all over again. For once, being supportive is the way to go