Complex sentence: Thirteen-year-old Phoebe Harte's younger brother, Mick, gets killed in a fatal bicycle accident because he chooses not to wear a helmet, which brings a great amount of grief and sorrow to the Harte family.
Split into simpler sentences: Thirteen-year-old Phoebe Harte's younger brother, Mick, dies in a bicycle accident, because he chooses not to wear a helmet. This brings an incredible amount of grief and sorrow to the Harte family.