Dreams of death can be extremely disturbing.

If it is your own death, or near death, that is naturally uncomfortable.

When it is the death of someone who is alive and well, the discomfort is even worse.

I can't really offer too much help. I firmly believe that Completing The Dream Protectively is the best method of working with disturbing dreams.

Death as growth

Death is a natural part of growth -- in order for you to grow as a person, some part of you must die. Awful as the dreams are, they usually signify that some part of you is growing -- or trying to grow. 

Death and rebirth

With experience, most of us find that death and rebirth go together so that, after the ordeal of the death-dreams, you will find wonderful and fascinating symbols of rebirth. For instance, A woman dreams that she has agreed to be executed instead of someone else -- she doesn't know who the person is and she has no idea why she agreed to sacrifice herself this way. In the next dream, she dreams about a tree and every leaf on the tree contains a cocoon. The cocoon is a symbol of the rebirth as the caterpillar dies, and is reborn as a butterfly inside the cocoon.