ISO Male born July/August 1956

I am still in search of my half-brother, birthname David, born in July or August of 1956 in Detroit, MI area. I learned two years ago that my mother, since deceased, gave birth to her first child before her marriage. Family history would dictate that the adoption may have been through a Catholic Charities home. My sister and I would like to find David and share family history with him. Any information is appreciated. lml