Something tells me that Mama Sou is wiser than her daughters, and hasn't been bragging endlessly about her picture-perfect, unbelievably handsome, well-behaved son to her subordinates. So they will be completely taken aback when an impossible dream walks in and smiles at them. ALL her co-workers will want to take her out for drinks in hopes of learning more about him and possibly getting closer.
It would indeed go to show that when not around/drunk on/thinking about boys, the vast majority of this universe's women indeed form some sort of functioning society. It's just the insanely-strong evolutionary pressure hijacks normal thought when around Sou.
We are seen glimpse of it in previous chapter, elder sister. They are competent. Otherwise new Sou would be having different kind of trauma from females.
I mean given the lack of men and how seemingly repressed everyone is , I’d imagine they’d understand
Unless she’s hiding the fact she even has a son, “bragging aside” based on the way they (women in this world) act, I imagine you’d never say that you’d have a son so your coworkers don’t worm their way into “inviting” themselves over to ur place lol