I have a sister-in-law who I am very worried about. I wondered if the any of following behaviors, actions, emotions point to a particular mental disorder.

Here is the lowdown...she is 38 years old with 3 kids from 3 different fathers. She solely lives off child support and food stamps. She currently lives with a boyfriend who is a doormat (really nice guy) and enables her behavior. She claims she doesn't work (or can't work) because she has Chronic Fatigue Syndrome. I do not believe this because she has no diagnosis from a doctor and won't seek disability insurance because she claims she'll be denied. She uses this as an excuse for everything. I believe she has a strong disability conviction and will never get help, even for the benefit of herself and her children.

The behavior I am concerned about her consistent manipulation of others to perceive her as a victim. She has very black/white thinking and is INCREDLBLY stubborn, the extent that she sabotages her kids wellbeing as well as her own. If you say the sky is blue, she says it's red.

I think her boyfriend will eventually give up and kick her out because of the way she talks down to him. She contributes nothing to the household, no chores, and complains when her boyfriends asks for assistance with rent/groceries.

Does anyone think an intervention help? Are there any mental illnesses that correlate with these behaviors? I am trying to understand her and I want to help her, but I don't know if that's even possible. Just looking for some advice out of desperation.