Pretty sure this manga is a statement at how japanese working culture is very distorted, and even destructive, from individual's perspective .
Nobody is even thinking to ask how the guy is doing, "is everything all right?", when it's clear that the guy isn't mentally there..
Everyone just expects you to be a senseless robot pretty much, and prioritize the work above all else. No matter if your family is falling apart, and if your daughter ran away.. Nobody doesn't care enough to ask, and everyone expects him not to open/tell about his worries to his co-workers...
It's only after work when people are drunk, when they dare to say what and how they truly feel and think..
I think in it's core it's a very sad way of doing things, and I'm not surprised that many japanese are just mentally a wreck, who have given their life working that way..