Brothers abound in the Gorgias, as do types of fraternal relations. I look for that form of fraternity in the Gorgias that Plato means to serve as a model or paradigm for the ideal relationship between rhetoric and philosophy. The Gorgias acknowledges deficiency not only in rhetoric but in philosophy as well, and recognizes merit in both rhetoric and philosophy, so that there is potential for the two to complement one another and when they do, to be of real benefit.
Weiss, Roslyn, "Oh Brother! The Fraternity of Rhetoric and Philosophy in Plato's Gorgias" (2001). The Society for Ancient Greek Philosophy Newsletter. 392.