Dear GCfasttrack
Why do you think your friend's problem is "unique." Plenty of cases of abusive relationship in these situations, where the primary derivative, usually the husband, subjects the derivative, usually the wife, to physical, verbal, emotional, and all sorts of abuse. I know somebody who was subjected to much abuse for at least a couple of years. During this time the husband would frequently threaten to yank the wife off the green card and the wife I heard lived a life of great dread and fear. she was unable to do anything except take these extreme injuries against her self respect and dignity. But then after both got their green cards, when she filed for divorce, for quite obvious reasons, the husband pretended to know nothing and thought this action was "out of the blue." It seemed like the husband was displaying the aymptoms of a typically abusive person--pretending not to understand why his wife wanted out.
My advice to your friend is to stop wasting money on attorneys and just seek out the real reasons behind his wife's decision. What you mention is unbelievable--that the wife filed for divorce out of the blue. Perhaps your friend perceives this to be "out of the blue." I am sure there was a lot of deep problem in the marriage for some time.
In my example the husband too wanted to prove the marriage was "fraudulent" and for a green card, which is very pitiful, because it clearly wasn't.