Hi, and welcome,
I'm afraid I have to second pretty much everything that Kazza has said. Sorry, my heart goes out to you.
My P son is undiagnosed, thanks to the professionals...who were utterly charmed by him. He's only moved out a few months ago. His exploitive behavior has escalated since, in part because he no longer has free room and board from us....and the way he fills his needs is through exploitive manipulation .
Be careful about the shows of empathy. Ps are very good actors.
You can't possibly protect every girl he will encounter from his manipulations, much as you might want to. I've come to the heart breaking conclusion that it isn't healthy for me to run itervention with others in his life. That has to be your priority , above all else...your own well being. And it is very likely that attempts to enlighten others in his life will alienate and anger your son.
I am currently struggling to maintain a realtionship with my son. I have firm boundaries, and very low expectations.
I can't advise you on your next step.
You will find more support at the general message board.
best wishes,
paradox