Stealing, Aruguing, No Friends, Overweight, Mood Swings, Difficulty Holding On To A Job. Thoughts?

I have a question about my sisters lifelong behavior. My sister is 28 years old , has never been able to hold down a job without getting fired after a little while, she has never been a responsible adult , steals alot, argues alot even with confronted with the truth. She can never keep friends for very long before she ends in them kicking her out or completely burning her bridges. She has always been overweight and always been sexually promiscuous. She is very moody and doesnt like talking to anyone about " whats been going on with her " . She calls family behind our backs and lies and tell them she is in trouble and needs money . Since she was a little girl she would lie to her friends parents about abuse in the house and there never was.