Praise be to Allaah.
It is not permissible to seek the help of the jinn in finding
about what the problem is and how to treat it, because seeking the help
of the jinn is shirk. Allaah says (interpretation of the meaning):
verily, there were men among mankind who took shelter with the males
among the jinn, but they (jinn) increased them (mankind) in sin and
on the Day when He will gather them (all) together (and say): ‘O you
assembly of jinn! Many did you mislead of men,’ and their Awliyaa’ (friends
and helpers) amongst men will say: ‘Our Lord! We benefited one from
the other, but now we have reached our appointed term which You did
appoint for us.’ He will say: ‘The Fire be your dwelling place, you
will dwell therein forever, except as Allaah may will. Certainly your
Lord is All-Wise, All-Knowing’”
The meaning of the phrase ‘We
benefited one from the other’ is that the men venerated the
jinn and submitted to them and sought help from them, and the jinn served
them by doing what they wanted and bringing them what they asked for.
That includes informing them of the type of sickness and its causes,
because the jinn can come to know of things that humans cannot; but
they may tell lies, because they cannot be trusted, and it is not permissible
to believe them. And Allaah knows best.