LOL! This is an amusing little fan fic about Shazam and The Justice League! The conversations are between Billy Batson aka Shazam and the other superheroes, but only Batman knows that Billy is actually a child. This of course makes for some really funny scenarios:
There is only one thing lacking in this. As seen in the links to related material Superman is canonically aware that Billy Batson is Captain Marvel, (Captain Marvel is the hero, Shazam is the wizard, and I will fight anyone who says otherwise. And afterwards, they will explode), so you have the perfect excuse to have both Batman and Superman running around after Captain Marvel like a pair of concerned gay dads.