Hi Pow3lly and welcome to the Forums.

So I can't really imagine how your 2nd char is goint to be useless by not facing the mob when he is only on follow. I think you mean if only your second got aggro by mistake or pat or something?However, you could do it like me, I have the Arrowbuttons unbound on Main and turn my alts (5boxing thy should always have the same direction )only with left or right arrow, or try to gain aggro with main , then I just let them follow again, and hit my (stop follow) button for let them walk backwards, just tick it a little so follow stops, that should face them to yours and you could keep on casting.