What is the best way to search for my half-sibling in Asia?

Question

I just learned that my dad (who is now deceased) likely fathered a child when he was stationed in Thailand thirty-five years ago. If I can locate one of his Army buddies, I might be able to find out the name of his Thai girlfriend and her last known location... but where should I go from there?

Answer 1

If you find the Thai girlfriend; she should be able to supply your sister's whereabouts!

Answer 2

Give up. Asia is the worlds biggest continent and people die early around here