I've had a lot of nightmares a year or so back... A recurring one was where my mother would die. It was horrible I woke up crying and sweating like crazy!
I just went on, didn't do anything special (at least not that I can think of), and now I rarely have a nightmare at all ( and never about my mother or anyone dying)... *knock knock* ( before I jinx myself).
So the best advice I can give you is, just let it happen and go on. It's only a dream.
Maybe you can talk to your friend about it, maybe that would help