While Shazam! spent a decent amount of time introducing these new people in Billy’s life, it also had to move relatively quickly to actually bring in Billy’s Shazam persona, and whatever moment Billy and Mary had before the former began his superhero journey ended up on the cutting room floor.
Billy Batson and Mary Bromfield have always been siblings in the comics, but as opposed to going the biological route as was the case for decades, the Shazam! movie pulled from Shazam’s New 52 origin story and had her, Freddy Freeman, Eugene Choi, Darla Dudley and Pedro Pena be Billy’s adoptive siblings at the Vasquez household.