The whole family is in mourning. For children, questions and anxieties may resurface much later because perception of the reality of death varies greatly depending on age.
Up to the age of 3, death has no meaning for a child. It is still in a magical world, death is not final, it is reversible.
Between 4 and 6, the states of life and death are not antagonistic. They are two different states. Death is always present. He is in heaven, but he sees and hears what is happening on earth. A child does not fear death as do adults, it feels immortal but it suffers from separation.