When you say the discs were glowing red was it just one brake or more?
If there was a dragging brake before take off you'd have thought the crew would have had visibility of this (brake hotter than the others) on the brake temperature page.
I'm thinking that this whole issue was likely fuel on hot brakes after taxi-out rather than a dragging brake, as I'm sure the crew would not have begun take-off if they suspected a brake(s) to be dragging