<human>: I never really had a great relationship with my sister. You could never depend on her for things or trust her for that matter. She stole things from family and close family friends in the past. But what recently came to light is absolutely insane. 

She had met a guy last year, and they fell for each other. 
The most fucked up thing about it though is that she lied to him about everything. She told him that she was medical resident at a NYC hospital. She lied about her education, and other things. Obviously he finds out that everything is essentially lie and that she is a fraud. A fraud that is 22 weeks pregnant with his child. 

She digs herself deeper into the lies by forging three letters indicating she's an MD.  The contacts on these forged letters have real doctors contact information. These doctors have never heard of my sister. She has told the father, either they try to work things out and raise the child or she will disappear forever. She will not give up the baby for adoption even though they financially can't raise a child. No one knows how much my sister makes or if she even has a job.

 I don't know what to do. Part of me wants to get her committed to see someone for professional help because at this point I really think there is a mental issue at hand here. She isn't making rational decision, and she keeps lying after she gets caught lying. She forged three different signatures of health care professionals. IDK WHAT TO DO!

Condense the text into a few key points
<bot>: Sister is pathological liar. Tricks man into falling in love with her, and ends up pregnant. Won't consider options other than trying to raise the kid together or completely disappearing.