#68716
As with any separation/divorce proceeding, it is imperative to consult a Family Law Attorney. There is no such thing as an "amicable divorce."
If the couple were married within the U.S., that State's Law normally prevails - again, by not being an attorney and only having my own (and, others') divorce proceedings to refer to, this is precisely why your friend should contact a lawyer, ASAP. It is my understanding that a Judge may grant a divorce in such cases without the non-citizen spouse present, though this is a sticky wicket and an attorney should be consulted.
Best of luck.