“H...Helper!?” I gasped. “How are you alive? How can you be...I saw you die with my own eyes! When the bomb fell, I saw...wait.

It sounds like he is in other world. At least that’s what he might feel like, almost like in a dream.
I’m glad they both survived and all Madeline, Lars and Sue moved on with their lives.

BTW: there is a writing contest going on by @neoxian. Perhaps you would be interested. I’m not a writer, as a matter of fact, I’m a reader. But you in my opinion have a great chance to win the prize. Here is the link, there is still more than 6 days left.
https://steemit.com/writing/@neoxian/neoxian-s-prodigious-and-desolate-post-apocalyptic-writing-contest