So when they die, we are not only grieving their loss but, if truth be told, we are bemoaning this new unwanted position in the hierarchy. Within the instant of your parent's death, your vision of the world changes. It is as if the world is indeed flat, and you are teetering on the edge trying to hold on by your proverbial fingernails.
You might start salting your food less. Or, you might say "what's the point of it all anyway" and salt it more. You might take up bungee jumping or crawl into a literal fetal position.
A catatonia takes over, and you resent the sky for its brilliant blueness because doesn't it understand that your mother is dead. You curse the birds for their insensitive singing and spring's first flowers for blooming so brilliantly.
Yet in this same sky and in the sparrow's song, you look for signs. Signs that your mother is out there, somewhere, and not just out there, but free of the pain and suffering that followed her like a faithful rabid dog throughout her life.
And if you are lucky enough to have such a sign, you are able to soldier on in the front lines knowing that when the Battle ends there is a new beginning.