When the kids are young the parents make all the sacrifices possible to give them a good education for a better future; to ease them from every responsibility until they are able to find a job and support the family. It's a really strong bond which is very different from the western culture where the importance of the family is progressively fading.
In Vietnam is very normal to live in extended families, 3 or 4 generations all living together and support each others. This is something absolutely inconceivable in places such as America or Europe, especially in the city. Infact, normally the elders are sent to the nursing homes as soon as possible. Perhaps it's also a matter of being a poor country since hundreds of years that create such a strong value regarding the role of the family. I find this surely admirable, but actually i could not be able to live with all my relatives and sibilings in the same house, i kinda like having my privacy.