A deranged Bronx man fatally gunned down three members of his family — inclduing his elderly, “Golden Girl” mother — inside a city housing project Wednesday morning before shooting himself to death, law enforcement sources said. The 44-year-old killer, who was due in court on a gun rap later in the day, blasted his 75-year-old mother, his daughter and her boyfriend in a horrific massacre at Castle Hill Houses around 9:45 a.m., police and sources said.