Ugg do not fuck her. that will only make it worse...
Pretty much what caution said. I don't think shes just doing it for attention, its sounds much deeper then that.
Those type of people will get attached very easily to anyone that shows care to them so tread carefully. The best you can do is to get her help, if her parents are as bad as she says then telling them might just make things worse. I would tell a teacher or guidance counselor and they by law have to get her help.