<human>: Not sure if this is the right subreddit; please let me know if I should post elsewhere.

I recently began my Ph.D. studies at a university and am working as a graduate student researcher in a lab. There is a postdoc who is also relatively new to the lab who just had a baby about ~~a week~~ 2 weeks ago.

The details are somewhat unclear but from what others have said, her husband was supposed to stay home with the baby. "Something happened" and she told our supervisor that it's no longer possible for her husband to care for the baby. When she showed up to work it was immediately obvious that she had been hit in the face, so all signs point to a domestic violence situation.

She has her own office down the hall so we only see her for various meetings and whatnot. She has been showing up to these meetings with her baby attached to her in a cloth carrier thing. Yesterday, she revealed her breasts to feed the baby mid-meeting. 

She is not originally from the US (where we're located) so I don't know if there is a cultural issue and she thinks it's appropriate to bring her baby to work with her, but obviously this is completely unacceptable. Our supervisor seems to be playing dumb and pretending this is not happening as he has not acknowledged it in any way. He is also a very socially awkward person.

I have been discussing the situation with the other graduate students and postdocs in the lab and we all agree this is wildly inappropriate. Should one of us talk to the postdoc/mom about this directly, or go to our supervisor? How do we bring this up? What should we say that isn't insensitive but gets the point across?

Summarize the given text in a few sentences.
<bot>: Coworker bringing baby to work, supervisor seems to be pretending it's not happening. Who to talk to and what to say?