I went through a long process dealing with people who I thought had NPD (Narcissistic Personality Disorder) but now I no longer believe in personality disorders ... it is all trauma repression and PTSD (Post-Traumatic Stress Disorder).
Coping mechanisms are perfectly treatable and NPD is simply a symptom on the wheel of trauma coping.
Compassion can cure ... and the person has to want the truth. They have to want out of the trauma coping matrix. They have to crave authenticity and bravely climb the mountain. If they say they can't, they are still in denial. But they hold the lock in one hand and key in the other. And they just need to realize they have the power to go through that door.
No matter how much they lie to themselves, never live there too. It isn't serving them the dissociation needs to be brought down by outside forces ... they aren't looking for supply ... they are looking for answers.
They can find the lost self ... it never ever really goes ... it only hides. And it wants to be found. Warning! They will attack and chew their arm off to escape if they aren't ready. It is not a pleasant process. And unravelling the damage of child abuse probably shouldn't be.