Why is death allowed to be painful?

I just heard a story about a boy who was known to have a terminal
illness, dying in his mothers arms. It was on the news, about him being
given his wish to create a play to be used in a professional football
game. His mother held him in her arms at the end and told him that he
could stop fighting. What is someone in that situation fighting to do,
and where's the medication he needs to relieve his suffering?

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