Family therapy? Unless her issues are derived from her family in this case she needs behavioral therapy for her assumingly sexual behavior. Why would she open up in front of her dad about the dudes she being inappropriate with?
I question this, most appropriate next step would be to investigate if they're safe at home. Because if he is abusive and learns more about the daughter's behavior and that the mom wasn't telling him (through family therapy), it could get ugly. If only it was an option
Weird answer to a weird question. "She(the girl herself) doesnt understand why she does these things" made me think of some sort of Mania component.