What do I do about random breath-holding in a brat?

Ignore / positive. Learning the skills of positive ignoring & positive parenting will often help this troubling behavior fade.Kids < 6yo don't understand peripheral vision, so you can "ignore" their event but still watch & be sure the kid doesn't hurt themselves.Don't lock eyes until the event is over, then interact in a supportive way.Learn a poker face & be sure your smile doesn't contradict your parenting command.