A 44-year-old man fatally shot his elderly mother, daughter and the younger woman’s boyfriend before turning the gun on himself in a disturbing burst of domestic violence inside a Bronx NYCHA apartment Wednesday morning, law enforcement sources said. The horrific scene of family carnage was discovered inside the home on Lacombe Avenue near Turneur Avenue, which is part of the Castle Hill Houses, at about 9:45 a.m., police said. Each victim and the shooter all were pronounced dead at the scene,