Psychopaths are really good at charming and manipulating people. For whatever reason, these women are buying the con. If an inmate is a psychopath (many are), he will only use people without any conscience. If your friend is involved with an inmate, you'll need to be around to pick up the pieces. No about of talking will convince a friend in this situation, though. The woman has to decide for herself that she's done being victimized, just like in domestic violence. It's hard to watch a person you care about put herself in these situations.