The loss of a child is a lifelong devastation.
I am in NO WAY discounting the devastation of loosing a child - I can't imagine (and don't want to) what I would feel if my duaguter were to die -
What I do question is the desire to keep the remains of the deceased. I would prefer not not remember them as a pile of ashes, but as the whole person they once were, and could be in heaven.