I didn't see a thread devoted to this story yet, so here it is. Since the story is relatively new, I'll try to keep it spoiler free. If you want to discuss, use spoiler tags when divulging specific plot points.
I liked the story overall, actually I wished it were a little longer. I wanted to know more about Sanderson and his father, and felt strongly for the characters. SK gives another perspective on the aging, one that has been alluded to in prior works but still manages to surprise.
About the ending:
I'm not sure what subtext or deeper meaning King has here, I think this is just more of a "this is what happened" kind of story, what did you all think?