drug rehab centres

They ARE prisons! Well, they are in the old re-education camps that were so busy after the American War.

For a vivid description check: < www.hrw.org/sites/default/files/reports … ToPost.pdf >.

It was prepared by Human Rights Watch. Their recommendations included:

To the Vietnamese Government
•  Instruct the Ministry of Labour, Invalids and Social Affairs (Ministry of Labour) to release current detainees in VietNam’s drug detention centres, as their continued detention cannot be justified on legal or health grounds. 
•  Instruct the Ministry of Labour to permanently close VietNam’s drug detention centres.
•  Carry out prompt, independent, thorough investigations into the use of torture, cruel, inhuman or degrading treatment or punishment and other human rights abuses and criminal acts in VietNam’s drug detention centres. Follow up with appropriate legal actions (including criminal prosecution) of identified perpetrators of abuses.

IF the intended "patient" is a Foreigner, i.e. not a citizen, they will likely be deported.

Drug dependency is considered an administrative offence - the police can simply pick you up - no court procedures needed. Your friend has broken several serious "felony" type laws in buying and using drugs.

So think before acting - consult with the 'patients' embassy or consulate, it's what they are here for. But, being 'square' civil servants don't expect much sympathy although they should help.

If he flew into VietNam, airlines are also expected (by law) to remove them which means he might get home. If he crossed by bus ...