Common questions I hear from clients include "Is he too old for this surgery?" and "Do you think it's worth it to her because of her age?" Invariably, and with a smile, my answer is "Age is not a disease." This answer is more serious than it sounds (My "mature" clients actually love that quote!). Cancer, kidney malfunction, a hormone imbalance -- those are diseases, which can be treated. But age in and of itself is not a disease.
It is never easy to talk about euthanasia and can be even more difficult when discussing it with children. The choice of how much a child will be included in the process may vary from family to family and child to child. You may want to give your child the choice by inviting them into the conversations and allow them to feel included.