Hi again Lindamunchkin- how scarey. Here's what I noticed: the source of the catastrophy was the sun (or son perhaps). Quite often people dream in puns, or at least I do and I would like to think I have company in my wierdness.
See what you make of this- I would think that your daughter has (subconsciously perhaps) a ton of worry about your grandson. She may be worried that he is in terrible trouble in some way. It might be that she has intuited that he is ill, or that he is just getting into some of the bad stuff that 14 yr olds do, or maybe just that he is getting into that frightening phase of his life when she won't be able to control things so much.
I would suggest that:
1. she gets her son a full check up with a dr. He's growing and it would be valid anyway. Then once they know he's fine-
2. If all was well, I think she should tell her son about her bad dream and how scared it made her. I would say that since we know your health is ok (eg. no medical cause for the bloody nose) she just wanted to also rule out any other cause- silly as it might seem- it would make her feel better- you know, like drugs...then just let it stand. He might not ever tell her anything, but it is good for him to know she is watching out for him either way.
Just a last word about warning dreams: we are often inclined to dismiss them, but it is also true that things we ought to worry about get around our denial when we are asleep. On the other hand, I would never expect that all dreams are precognitive or literal. I have dreamt of the death of a child or parent and all are still living years later. It is often more about the dreamer and his/her relationship with the one s/he dreams about. But you know, a doctor's visit never hurts, does it? Good luck, let us know how it turns out. T