Four people are dead, including the gunman and his toddler daughter, following a shooting at a Brooklyn apartment this week, according to police. All of the deceased were reportedly related by blood or marriage. As WABC reports, 27-year-old Terrance Briggs; his daughter, 1-year-old Layla Briggs; his stepfather, 57-year-old Lloyd Drain Jr.; and 15-year-old Lloyd Drain …