To naturalize, I believe you have to show good moral character, etc .. and certainly not obtained a GC by fraud.
Therefore, personally, this is what I would do if she has her GC. If she doesn't have her GC . . then maybe invite her back to China for a "reconcilliation meeting'with her parents" and offer to buy them a car when they arrive if all goes well ... then ...
1) Notify USCIS, and send proof, and suggest that doesn't get naturalized, and if possible start proceedings to recoke her GC (probably impossibe, but why not).
2) Notify the USA embassy in China, to inform them in case any of her family members try to come fraudulently and mention claim she just had a abusive husband. Many embassies have a special email to report fraud. Of course, the embassies get these kinds of the emails often, and ignore them, etc .. But why not, ... you might be helping future fraud.
3) I strongly doubt your congressman would also FAX UCSIS to make the same requests, but you could try to show the evidence and try. With all the anti-immigration, maybe they will try to score brown points.
Again, before anyone says this is very unlikely able to be effective, I agree, but you could just do it, then move on ... It might also even help you when you explain why you did a new K-1 in a few years.
And just to be super clear, I am only saying to report the facts and truth. Don't exagerate or make up any stories. be totally factual so others can make a decision. and send proof .. must have proof