24-year-old Robert Droelle of the Croswell area was arraigned Monday on a charge of second-degree murder in the death of his 4-month-old son.  Droelle was arrested and arraigned Monday, a week following the death of Jordan Droelle.  The young boy was taken by ambulance to Port Huron Hospital with severe head trauma before being airlifted to Detroit Medical Center Children’s Hospital April 2, according to a statement from the Michigan State Police Caro Post.  It was reported that he died of his injuries April 9 having been on life support.  The child was in his father’s care at the time of the injuries, and they are consistent with having been shaken. Reports say Robert Droelle is being held in the Sanilac County jail on a $750,000 surety or 10% cash bond. A pretrial conference is scheduled for 10 a.m. April 18, with preliminary examination set for April 24^th.