Looking for possible sister or brother

Dear Sir or Madam:

My wife found out that she possible has a brother or sister that her dad created while he was in the Vietnam War, 1969. The mothers name was Tuet Vanthie from Long bein. The baby was born between June or July of 1969. Don't know if he or she is still alive or what. The fathers name is Jesse Galvan. If you know anything please email me at the address given

Thanks,

Jose Campa