But you still haven't said the name of the crossword?
I expect you're right. but Collins says that BR'ER is the prefix for brother in southern negro dialect. I don't see how that can be right.
The answer from wikipedia is that Br'er Rabbit (also spelled Bre'r Rabbit or Brer Rabbit or Bruh Rabbit) is a central figure in the Uncle Remus stories of the Southern United States. He is a trickster character who succeeds through his wits rather than through strength, tweaking authority figures and bending social mores as he sees fit.