Oh, this made me sad. The classic story of a child dying in their mother's arms will never not be heartbreaking. Your writing style fits the narrative of a dying child very well: I really like it that you didn't make him overly naive: writing children is a common stumbling block for many, but you aced it!
Read the story now
I said earlier that dying children are sad as a default. This story rides on that quite strongly, and I feel that it could've been even sadder if there had been something more to it. But then, it is a very brief piece, and it is difficult to put a lot of plot in such a small amount of words.
You managed to break many a heart with so little. The minimalisic narrative not only shows us the viewpoint of the child but also his mother: her desperate hope and sadness. I think that hit me even worse than the child's fate. Overall, great job.