Whether state disorders are temporary or permanent depends, but yeah, PDs are basically incurable. BPD is the only one with an evidence-based, standardized course of treatment, and is often changed to something else when it's considered to be in remission, which happens when less than 5 criteria are met. That mostly reflects changes in behavior and integration of disordered and non-disordered personality traits, though. I would be extremely skeptical of anyone who claimed that they'd been cured. Usually, those are either grifters, outright lunatics, or lunatic grifters.
EDIT: You do ask a lot of questions that might be more appropriate for a talk page or off-topic thread. I think they're technically relevant since Sam appears, based on circumstantial evidence, to have severe Petulant BPD, but this really isn't a general thread on PDs.