My father was drafted into the Taiwanese marine service for mandatory military training and service long ago before he came to the United States. He was a forward observer (I don't know why the put him as a scout/observer, his vision is crap but I don't think they really planned on fighting the mainland anytime soon). Agusto, did your cousin serve in the US Marine Corps unit stationed around Taiwan or is he Taiwanese serving in the Taiwanese military?
Either way, if he is still in Taiwan I would suggest you not get him anything with ATS-34, it seems to rust easily for stainless and Taiwan is very humid and very hot in the summer. The tap water is many of the regions aint so great either. I speak from first hand experience about the Taiwan stuff as I visited there quite a bit when I was younger (still young but I'm talking about even younger). Price range is important too, I don't have much experience with rusting as I maintain my blades regularily and rust never bothers me, but I'm sure that BG-42 and some of the newer stainless steels will work fine in Taiwan.
-chang