Interesting, it seems like usually it is people moving from the far east to western countries that get hairloss.I recall my dad who enlisted in the military during the Korean War say that he left for Korea with a full head of thick hair and came back bald in just a few years. He was convinced he had contracted a parasite while there, that caused him to rapidly lose his hair. Maybe certain parasites can trigger this phenomenon, and it depends on each person’s constitution and gut micro biome as to whether they can overcome it or at leas keep it in check.
If hairloss was caused by some parasite I'd suspect demodex mites. Maybe when enrolling to the military he got some nasty vaccines. Would be interesting to know what he's been eating there too.