How old is this child?
I would be VERY worried about the fact firstly that she is driving without a licence and secondly that obviously this child is nowhere near old enough to be sitting in the front seat!
I would most definitely be discussing this issue with her and pointing out that shear laziness is no reason to put her child at risk.

I would find a video if possible of crash test dummies of a young child and show her, she obviously doesn't think.

Regarding the milestones i think that is a little harder and each child is different, just becuase they don't reach a milestone at a certain age does not mean there is a problem.
One boy @ MG is 16mths old and still wont walk, he is the only one left out of ALL of the kids to not be, yet he has done other things earlier.
Depending on the issue i would broach that subject lightly.

GL