Not an easy thing but perhaps it is relevant to let the kids know (as if they didn't) that death is part of life and natural.

My father died when I was 9 months old - at least they had him for 10 years. Maybe you don't miss what you never had - maybe - but believe me - I would NOW have preferred to have had 10 years of memories. Rather than 36 of a grieving mother.

Life is cruel.