Looking for a child Given up in Bahamas

Good afternoon, Im looking for help in beginning the search to find a child my mother in law gave up for adoption in the bahamas when the child was 3 years old. She would be approx 41 now i believe, My boyfriend would love to get in contact with his birth sister, Can anyone help me in finding out when to even begin this search.??

My Sister In - Law located my 79 year old Dad's Biological Sister with the DNA Test from Ancestry .com. and I hear through the ' Adoption Grapevine ' . ' There is another Test . That gives more answers or information than Ancestry .com did '