It doesn't strike me as odd in any way.
Don't lots of people go to TGI Friday's, or Applebees, or similar, with lots of children in the party at times? These are all technically part-bar.
Sometimes the best restaurant in town, and/or with the best/only vegan food options, are restaurants attached to bars. In some communities, it's the only place that's open at a certain time.
Plus, less competing noises (the later it is, the less likely it is that cars and human cries of glee from people on the sidewalk, are going to be a factor that ears have to rule out along the way; because eventually people go to bed and take themselves out of the equation).
The millions of varied things people have said about this call probably have my head aching at this point, lol; but still, I thought we were pretty clear as to why Gabby's mother thought it was odd, "She never called him Stan."
I was assuming that Gabby's mother's unspoken continuation of the statement was, "She never called him Stan... but Brian certainly might'."
Lastly, I thought Gabby's mother in fact said her father's name IS "Stan"; thus using it as an acronym for an emergency situation would, IMO, be super weird.