I can j-u-s-t understand a mum wearing a onsie IF her child was old enough to walk the distance from the car to the school gate, without crossing a road. However, wearing slippers and PJs out of the car or worse walking like that to school
I would have thought it embarrassing for the child. More importantly, it is sets a bad example.
I must be old fashioned; when necessary, we still drive our GS to school, normally dressed, but then we usually stop for our breakfast
on our way home.
Years ago, I'd driven my DH to the airport rail station in PJ bottoms, slippers with jumper and jacket (in winter) on top, when my car also stalled, twice.