There's good chance for her
If your friend doesn't get RFE(request for evidence) from INS, she should be able to get GC. If she receives RFE before divorce and her hu*****and is still willing to provide info reqested, she can get GC.
There's good chance that she won't receive any RFE.
On the other hand, she is out of status as soon as she divorces her hu*****and. It's a gray area. If INS doesn't find out that, it's ok for her to stay.
Why does she want take the risk? Try to stay in marriage until she gets GC.
I feel sad for her and her hu*****and. I guess her hu*****and is another "transporter".