Dear Rohan and Mr Joshi,
In the eyes of law, once a couple got thier marriage registered, it is a legal marriage, whther it is disclosed to the parents or not.
Secondly, once she got Mutual divorce, then there is no appeal.
But in rare cases, if court found that one person had make fraud to get divorce, then court may hear its appeal/revision, but for that you have to work very hard to prove this thing.
So first of all you have to search your friend and try to stop her else, it will be very tough to stop second marriage of the boy.
you may suggest her that even without divorce, they may get marriage in general public.
adv.kamal.grover at gamil