I can understand that PTSD is a terrible thing for those affected - Is it an expensive syndrome to treat long-term?
Like all mental health treatment, treatment for PTSD can be relatively inexpensive or very expensive. It isn't like antibiotics for an infection -- take this pill once a day for a week and Bob's your uncle. The duration of the treatment varies depending upon the individual.
Sometimes the treatment works and sometimes it doesn't. Some people will recover without any treatment. Some victims of PTSD who receive significant treatment never recover and are never again able to hold down a full-time job.
Different people are, well, different.