Looking for a Vietnam/American child born to Harold G. Davis

Harold had been ordered to leave with the Marines on a plane.  There Harold had left behind a woman who was pregnant with his child; never to see her again. I don't know if she had been killed or may still be living.  In any case my brother has been deceased since 1976, never having any other children and has never been married if the child is still alive I thought that it may be some healing for my mother to know that Harold had a child.  Also, our family would be very excited and thrilled to find this child.  He was serving during 1967 to 1969 with the Marines.  He also, befriended a small boy who's name was, Bong.  Any information would be helpful.  If the child and/or mother are still alive, we'd like to make contact.