Your words have just confirmed my belief that you come from South Vietnam, because you seem to know nothing about North Vietnam at that time. Even if you were only a child or born long after this period, you should have known something from your parents and grandparents.
In 1978 - 1979, ethnic Hoa people could not even live as normal people, let alone to be assigned as party secretary in the border area. Any Hoa cadres who held high positions in party were purged, even people who knew nothing about China, not speak Chinese and had lived in Vietnam for generations. To be fair, this situation was caused first by Chinese government who wanted to use Hoa people as fifth column army in post-war Vietnam. Vietnamese government was just reactive to protect the economy and nation.