Who knows our father - Roberto A. Castro- born 1966- Roxas city?

Dear Sirs,
I am Noy Castro. I were born in 1966 in Vietnam. My father's name is Roberto A. Castro.He was born in 1929. He is a Filipino.My mother name is Do Thi Thu Lan.My father came to Vietnam in 1964 as a soldier of America Army. His job at that time is mechanic. He got married to my mother without marital certificate and has two chilren- I and my younger sister. Her name is Ney Castro.He was demobilized in 1970 and had to returned to his country.The last office where my father served for the America army is the federal No 5,the factory No 5 mending Military stores at Nhatrang city. We lived at the address of 58 Hung Vuong street, Nhatrang city, Khanh Hoa province, Vietnam. After the war, my mother and us must moved to many where for living so my father has been unable to contact us any more.My mother have clearly rememberd the city where his family have lived is Roxas city. Now we have had many photographs of our family taken as I and my younger siter were childen and a my birth-certificate. Because of the war and moving, my parent coudn't do a birth- certificate for my younger sister.
Dear Sirs,
My parent is older and older. They have been unable to wait and look for together. Although we have tried our best to send many our photographs and documents to many where but we now still receive no answer. We are really happy when you help us to know where my father is now and if my father is alive or he has now died. I am looking forward to your letter.
Yours sincerely,
Noy Castro.
Email: n_vminh@yahoo.com