Sadly it made my ex-wife worse off than before - she went from a functioning anxious person to being completely overwhelmed by anxiety all the time.

Unfortunate, the whole landscape on this is littered with mines and finding truly knowledgeable help is difficult, most seem to just push their favourite flavour, regardless of the patient.

Any successful form of trauma treatment will first make it worse, because you open the can of worms and begin to go deep. Unfortunately, many therapists are not very good at explaining that up front. If you only have a few sessions, it is basically guaranteed to make matters worse. That's a sign that it is working (but maybe a sign to switch therapist if it wasn't explained well and cautioned about; making sure the environment and person is ready for it should happen first...).

> But just because something is not provable or falsifiable under current scientific knowledge

Do you mean unproven instead of "not provable or falsifiable"?

Something not being falsifiable would mean that we can't detect if it's doing anything even if we tried, which doesn't bode well for its effectiveness.