But had it been done so many times when Angelfish wrote this? I'm not sure of the dates but I thought a lot of the child-abuse stories were later, and just maybe inspired, consciously or unconsciously, by this.

It's a relatively well-worn theme. Although it's more worn now. *g* I know very good writers like Georgina Kirrin tackled it -- and not so good writers. It's not a theme I enjoy either, but I think Angelfish did it well.