When explaining death to younger children (around preschool age), the most important point for parents to stress is that:

The child is loved and not abandoned

Explanation:

The death of a child is the worst trauma and worst condition for parents. It is the worst experience and trauma for parents. It is considered as the single stress-or that parents go through. Parents and specifically father is more responsible for their children security and the well being.

They are being more affected by losing their loved ones and by losing their promise. Parents mourning their child in many ways such as a classical grief response. The trauma through that parents go through is very hard. It goes harder when they have to let go of the memories related to their child. So its a very bad experience for parents.