It won't reveal what he was doing immediately prior to loss of control (i.e. texting). That will have to come from the phone or phone company records. And if he was just reading....no record.
Next generation might include a black-box camera pointed at driver. Not acceptable to me, although I don't drive distracted.
and today’s vehicles also have “blue tooth” connectabilty for hands free device operation while driving...
all information is available via the obd2 port that is accessible by a laptop computer...
this includes speed and braking attempts at point of impact...