"NPD are delusional, grandious, they live in webs of lies, delusional fantasy worlds, there is no truth in a NPD, so to try to find truth in a NPD is futile because there in no truth in the NPD, you can not find truth in a lie."-- You posted.
The above are the truest words ever written to describe an NPD. Frankly, I see ABSOLUTELY NO HOPE WHATSOEVER for anyone choosing to be a narcissist. Denial is in their emotional DNA. You write that psychotherapy for ten years is about the only answer. It isn't. Won't work. Think about it. Now really.
The ONLY answer is Jesus; but only a bad case of NPD thinks that they can even BS HIM! Believe me, I know. I see it every day.