With the side fear that something worse happened to him (or he got tossed down the well with Nancy) AND HIS BODY WAS NEVER FOUND.

I can't recall if Percy's mom knew much about the abuse? Like, I'm sure she heard Percy and Nancy talking about it, but she seemed to mostly be "You are living in sin! In my house! And you got fired for bad behavior and lying about your employers." as opposed to actively "These people are saints HDU suggest they aren't who cares how utterly miserable and scared every single one of these kids always looks?" like the Reverend had been.