Hello!
This is an excellent question. It's difficult to answer for a few reasons. One: I am not a licensed dream analyst (or any kind of mental health professional), so I'm afraid I can't give you an "official" answer. Two: so much of a dream's meaning is unique to the dreamer's experiences and worldview; since this is your aunt's dream, your aunt will ultimately need to be the one to determine what the dream means to her.
However, I can understand how disturbing a dream like this might be--particularly since, as you mentioned, dreams are such an important part of your family life and beliefs. If possible, I would recommend talking to a licensed therapist about this--one who understands and respects your family's beliefs and can work within that context to help your family better understand your aunt's dream. However, if that is not possible or if your aunt is not willing to try that at this time, I would encourage her to sit down and really think about the different elements that were present in her dream. She might even want to write it all down, to help organize it all (as there may be many pieces to this puzzle).
Some questions she can ask herself that might help her to work out what was going on in this dream include:
1. What emotions did I experience during the dream?
2. Is there anything I know about this family member that might be connected to what happened in this dream? (This might not be literal--for instance, maybe your grandmother often "beat herself up" about certain things, which your aunt may then have visualized literally in her dream.)
3. Could any recent events, thoughts, or experiences have triggered parts of this dream? (For instance, maybe she saw something violent on TV shortly before this dream--or, maybe she's been worried about not hearing from your grandmother. Worry can often manifest violently in bad dreams.)
4. Could any memories have something to do with this dream? (For example, let's say your aunt remembers your grandmother once hit her hand accidentally with a hammer. This dream might be an exaggeration of that memory, again possibly triggered by any worry--conscious or subconscious--she might have now around how your grandmother has been doing.)
I wish I could give you a clearer answer; I know it would be more comforting. But I hope you, and your family, find this info helpful. And again, when in doubt, it never hurts to seek the counsel of a licensed therapist or counselor who specializes in dream analysis--especially if your aunt has any more dreams like this one.
Take care,
Kim