Yes, she's in a shitty position, but you both (and her parents) have to recognize that all the (likely) outcomes kind of suck, and its not their fault. They just have to do what's right for the girl, and tell the grandparents respectfully that there is no way they're attempting to force their child into marriage. If they won't cut this thing off, she has to. If she gets cut off from her grandparents financially, then it happens. Her parents have to support themselves then, but unless there's something seriously wrong with them, they can. If worst comes to worst, and her parents side with the grandparents, she needs to get out of that environment ASAP. The longer she allows anyone involved to think she'll go through with this bullshit, the harder and harder it will be for her to pull out of it.