FLATBUSH - Relatives of a Brooklyn family are grieving for their loss and hoping for a miracle after a fatal pedestrian accident that took place Wednesday.Rachel Fronbrum remains in a coma Friday after she and her children were struck by an out-of-control car while they were walking to school. Five-year-old Christopher Fronbrum was killed. His siblings, Joshua and Adeleine, are recovering. The driver, 52-year-old Bertilde Gabriel, was arraigned this week on charges of criminally negligent homicide.The incident is the latest in a series of fatal accidents to strike Brooklyn. Residents say it is time for drivers to slow down and be more cautious before another tragedy occurs.