Confidentiality. 9: The law relating to whistle blowing

Alex Black, a staff nurse on an intensive care unit, was extremely concerned about the lack of adequate staffing levels on the unit. He had put his concerns in writing to his manager, but no action appeared to have been taken. On one weekend there was such a lack of staff that it was impossible to ensure that one nurse was attending every patient on a ventilator at all times. A young girl, injured in a road accident, was brought into the unit following surgery, and was placed on a ventilator. Alex was asked to monitor her care as well as that of another patient being ventilated. The girl died and Alex considered that this might not have happened if there had been adequate staff levels. He knows that the family are ignorant of how low the standards of care were and is anxious that they should be notified. Would it be lawful for him to tell them?