Depends. Sometimes vasovagal syncope is sel limiting, others it is a recurrent problem and requires attempts to treat with medications. The most important thing is attempting to stay hydrated and eat small frequent meals. If you feel like you are about to pass out sit down and put your head in between your legs or lie down on floor so if you do pass out you don't hurt yourself.
Normal reflex. This is a normal reflex, only exaggerated in some people, so a "cure" for normal doesn't really exist. Highly effective treatments are available, however, to reduce the likelihood of loss of consciousness. These include physical training, medications, and in rare situations, pacemakers.
Treated yes. If someone has vasovagal syncope they always have the predisposition in the right circumstances. The symptoms can certainly be treated and controlled. Life style modification are certainly important in addition to medications.
Yes. Fludrocortisone is very effective or increased salt intake.