TCKs from non-Euro-American backgrounds in many ways have a double helping of TCK grief. There was the grief of being on the outside while in school, and then the grief of moving on to another culture, maybe the home culture, and not fitting in there either.
This “home” is the place you have been looking to for many years; it is where you are supposed to belong to; it was pasted on your class poster for 12 years. But now that you have arrived "home" why does it feel more foreign than the foreign place you just left?
Their mutual emotional home will be this third culture, and that culture will be based on the shared experiences (some wonderful, some painful) of living in and around different cultures--and it doesn't matter much which cultures.