I have never had a prophetic dream myself(yet) but I certainly do believe in them. It's quite possible you had the dreams about your 2nd husbands passing so that you would be better prepared to deal with it when it happened.

To use dreams as a method of "scrying", just before going to sleep, write down a question you would like to have answered in a dream. Immediately upon waking write down any dream that you had. Keep trying if the dream doesn't come the first night.

~Dreams are your own unique source of guidance and healing~