I'm not looking to diagnose him. I'm trying to better understand the "spectrum" and get a better handle of some of his behaviours. If I conclude in my head this is a fitting issue, I can better handle situations without taking things personal and feeling wounded. I'm not going back to him and telling him (or anyone) he "has" NPD.

Having an adult son with special needs, I'm all too familiar with the process of getting a proper diagnoses.

I suspect many people with this disorder are unlikely going to get tested.