How is he "out of his element"?  If you can't confront a child living with you about something you're concerned about then you don't need to be the caretaker.  

You're not making sense.  She has no friends but she can't go online because of her friends? She's not allowed to go out but she can do stuff with kids in the neighborhood?  Which is it?  And he keeps her phone?  I just don't understand.  Why is she living with him?  Did she do something severe that he has her on such close lockdown but is too afraid to say, hey, what's going on with you lately??  huh2