How do I communicate the themes of death to children?

Perhaps a melting ice cube. It demonstrates the slow draining of life implicated in the woman's issue of blood.

Perhaps an empty candybar wrapper or a lost pet could help communicate a Jairus' grief.

A tooth paste tube:

So ... when you have a woman who has been hemorrhaging -- bleeding for
twelve long years -- she has in the Jewish sense, been 'losing her very life'
for those twelve years. Life has been oozing out of her -- seeping out of her.
Like a toothpaste tube being slowly rolled from the bottom, she has been leaking
life for a long, long time.

What the end of the fifth chapter of Mark says is that all of us are left for dead, all of us are dying, all of us are having the life drained out of us like a toothpaste tube being viciously squeezed. All of us are limp, dead corpses waiting to be carried off -- Until! -- Until we encounter Jesus. Until we are touched and we touch.