This is a really cute idea! Arthur is so sweet in this, and poor Alfred, searching for Mattie. (Invisibility really is an appropriate power for him, but with what Arthur said I kinda doubt he escaped.) :'(

And wow, you managed to include the first aid theme! <3

Though things are fine now, I'm afraid things will repeat history and Alfred will rebel, and Arthur's parents death will end up being caused by supers...