I would not depend on facts from a housemate.
Concerning Ho Chi Minh, he was not of Royal Blood and he could not establish a Royal Dynasty.
Ho Chi Minh did however by force establish a Communist Regime in North Vietnam, that in time invaded South Vietnam and united the country under Communism.
Concernig the history of the Nguyen Dynasty and succession of dynasties information can be obtained here:
http://users.panola.com/vietnam/crown.html