looking for my bio brother

I was adopted. I found my bio father in 1988 and my bio mother in 2000. I have been informed that I have a brother that is 18 months older than me. This is what I know. His name was/is Carlos. He was born in Frankfurt, Germany . His birthday is Sept. 26, 1959. He was adopted by a military family. They went back to the states on or around April 15, 1961. I think they went to Chicago. If anybody fits this discription on knows anyone that fits this description, I would love to hear from you.:)