At her age parents family cant control anymore as to what she wants to do. with regards to passport being held by her family i doubt its true and it doesnt matter they cant deport her unless she is here and working illegally. If she truly loves your friend she will introduce him to the whole clan no matter what. Tell your friend prove to her family he is genuine and give a surprise visit in her house at night and meet her family (if she is not hiding anything aside from the relationship it will be alright but if she is married thats a very big problem). or maybe you can do some investigation by knowing who are the people living in her house and that will give you a clue.
