Warning. Triggers for CHILD ABUSE and CHILD CRUELTY. If seeing such distresses you (at least moreso than child cruelty SHOULD distresses ANY normal right-thinking individual) or can trigger a severe response in you, DON'T CLICK ON THIS. Some Golden Age stories are not all happy, and as you'll see from this story in 1948-- if you thought Billy had a tough childhood before, you didn't know the half of it.
How did Billy placate his old miserly uncle? He was told to go steal for his uncle Ebeneezer. Even in the face of being repeatedly WHIPPED, he instead sold pencils and begged in the cold in threadbare clothes and shoes that had huge holes in them.
Taken by a policeman to a nearby hospital, for the first time in his life, Billy was treated kindly. However, his Uncle Ebeneezer ran true to form.
Later, Ebeneezer became the leader of a band of child thieves that he blackmailed into working for him, sort of like Fagin in OLIVER TWIST crossed with Ebeneezer Scrooge, and with the worst qualities of both. Interestingly, Captain Marvel didn't immediatley recognize Ebeneezer, but Billy definitely did, although Captain Marvel said the face DID ring a bell. If Billy was Captain Marvel, you'd think he'd know immediately--if he was a seperate person, he wouldn't recognize him at all. Evidently the wisdom of Solomon and the courage of Achilles modified the original Billy's memories to a certain extent, but didn't eradicate them.
I'm happy to say that Ebeneezer wound up in prison after that--for loan sharking and theft. They should have added child abuse and abandonment, to boot!
But if the Geoff Johns interpretation of Billy as a bitter and somewhat conniving young punk doesn't seem true to the original idea---well, yes.
And one might see why the wizard Shazam picked HIM out of all people in the world as the one most "pure of heart".