It is natural for people to shy away from the reality of death. After all, the fear of dying is the root fear of all fears. Yet this refusal to acknowledge the impermanence of our earthly existence creates a deep anxiety that inhibits a person’s spiritual progress. Put another way, if we are to progress on the spiritual path, it is necessary to fully accept the impermanence of life and the certainty of death.
The ego is terrified by the thought of death, since it knows that it will cease to exist when that time comes. As a self-aware living entity, the ego wants more life; it seeks to survive this threat. But the ego knows, deep down, that there is no avoiding death, so the it deals with the inevitability of death by avoiding the issue.
By facing the reality of death, we are facing the root fear of all fears. By ridding ourselves of that fear, we are able to live fearlessly without the normal requirement for security and permanence that holds most people firmly in its thrall.
The Buddha left detailed teachings on what happens to a person when they die. This is tremendously helpful for a person seeking liberation from the fear of death.