They probably just want somebody to push the student to study. I don´t know what s/he is studying, but I have had to help some of my EAL students with A level subjects and I just read their book and explained it to them again, and voila that´s all it takes. Some of our students have been spoonfed so much that have lost the ability of self-study. Just ask what are the subjects he is studying. It may be that he just needs an adult with common sense to help him. Explain the situation to the parents and how you feel, and see how it goes. Of course, if you want to teach this student, that is. Sometimes, it is important to be able to say "no".