It is important to feel the anger without judging it, without attempting to find meaning in it. It may take many forms: anger at the health-care system, at life, at your loved one for leaving. Life is unfair. Death is unfair. Anger is a natural reaction to the unfairness of loss.
On Grief and Grieving: Finding the Meaning of Grief Through the Five Stages of Loss (ed. Simon and Schuster, 2005) - ISBN: 9780743266284