This is actually a good question, unfortunately there is no good answer.
If you have suffered such a loss, my sympathies are with you.
In a way, a grieving person grieves because they have suffered a loss,
their own personal loss of a friend, a child, a companion, we grieve for them
In a way we do not for the millions of "strangers" who share the same fate.
In a way we grieve for ourselves.
Nothing is created or destroyed, but only changed in form, and so it is with death.
Douglas Hofstadter wrote several books, inspired by the death of his wife explaining
how every action, interaction, every expression of thought and personality,
permeates, the lives of others and becomes a part of the history of life.
I was just reading
Mary Poppins, where in one chapter it is explained that we are all
of us derived from star stuff, stuff of the universe. Again, to die is to change one's form.
I am old now and have lived through many losses of life, ministers try to console the
living with promises, explainations of eternity- still we grieve, we suffer, hurt, feel a loss
that somehow seems cruel and unfair. Like a terrible injury, it takes time to heal.