1. The concept of "preparing for death" is alien to the Jewish tradition. Psalm 71 emphasizes retention of hope: "cast me not off in my old age when my strength faileth, forsake me not... But as for me, I will hope continually". Hence many sources suggest that it is not in the dying person's interest to disclose the nearness of death.
2. We deny death because it takes all our intelligence and all our heart to understand death.