URGENT! Just a quick question

I need to know for a friend, If she came here on a visa to help her sister and while she was here her and her husband who by the way was already here and is a citizen now decided that she should go ahead and apply for her Green card to stay here as his wife, And the process is already started and she was told she should have her visa in about 3 months..... but now the marriage isnt going so well and she is afraid that if she doesnt stay with him they will send her back home. Is this possible or does she still have the right to stay and recieve her green card reguardless of wether or not she is married to this man still?