I feel that the extra “narratives” to be the thoughts/emotions of Xanther. She has learned how to express her inner voice. For her to be so young, a great deal of her thoughts are understandable. I think that she is dealing with a deep, deep inner hurt that she can not let go. Could the raindrops represent people, thoughts, or inner feelings?
For example, two of the “raindrops”: “first flipping the horizon over as if to reverse gravity, but that only makes the rain fall back into the clouds.” “If Xanther froze it all, suspended the whole storm with a wish, a wave of that impossibility with a long finger, which she tries to do now, if just in her head.”
Now, could we count the raindrops as tears? In these statements, since she has lost her father, could that be a reason for the thoughts and emotion. Not one of the “raindrops” represent happiness, they are all just… Sad.