1. Nothing that I can think of should be added or tweaked. Perhaps in the first paragraph, a very very brief and still vague indication of why the Mother is leaving?
2. The images the storm paints, of the cracked smile in the pavement, the weeping coat, the kingly crow, and the monsoon all indicate the sinister fear of the piece--adequately painting it as a night terror. I also like that the mother is "breaking her back" to help appease the child, as if the child itself were feeling a fear fraught with guilt in the throes of its dreams. And the conciseness in which it is presented captivates the attention of the reader--illustrating the simplicity of a child's mind, and the horrible realities dreams can concoct.
3. I accidentally caught the description before I read the piece, but I'd have to wager if I were looking at it the first time, I would think the writing is about some slight form of a child's fear of estrangement, but also perhaps a premonition of the separation parent and child all eventually experience as children grow older and leave the nest. The mother does not fear the storm, but fears the crack, which means perhaps the child is the one who fears the storm--the oncoming onslaught of loneliness and chaos in life.
4. I don't think it details your relationship as well as it could. It shows the determination and sacrifice of a mother, but many mother archetypes have that same trait. I don't think it's a bad thing that it doesn't explore your relationship's individuality, because as it is it can reach a wider audience and will also leave room for discussion.

Overall, I really enjoyed this piece. There could definitely be some room for improvement, I'm sure, but there's some very strong elements here, and I believe the words can easily reach and stick with the reader.