Given the sensors in modern cars, would it be possible to detect submersion and roll down windows automatically?
If the window opening mechanism is still working, better to let the driver & passengers make the decision on whether or not to open them and when. If the mechanism isn't working, then the question is moot.
The odds of (1) car driving into water * (2) person is incapacitated * (3) rescue is available and can access the car but can't open window have to be so low as to essentially never happen.