No problem falling on sport climbs, right?

I think he was lucky it wasn't worse.

"Do you wear pads on your vagina too?"

The belayer screwed up on that fall plain and simple. Just locked off the rope. The poor guy hit the wall with much more force than he would have were Mr. Keesee manning the belay. Ropes can end up in odd places in the heat of the moment on hard climbs. A nice soft catch, and that guy would probably been making another attempt later on.

please tell us exactly what he should have been doing either before the fall or in the 1 second he had to respond to the realization that the kid was falling that would have prevented this injury.

The wall appears to me to be concave, which makes the soft catch a tricky judgement call, and in fact seems to be the worst possible concave configuration, very overhanging or even roof-like terrain with the pro set back in on a less-steep wall underneath.

Ultimately its a judgement call

In this case helmets are a moot point. He broke his ribs and a thumb.

Ropes can end up in odd places in the heat of the moment on hard climbs.

JLP is right; I don't fall much since I've been almost entirely a trad climber. I'd guess somewhere between 100 and 200 falls total, with, as I mentioned, four inverted ones. On one of the inverted falls, I would have been either dead or paraplegic had not my belayer (Jim McCarthy) literally jumped off the boulder he was belaying from in order to take in enough rope. I'm grateful for having a belayer who understood what the situation demanded and wasn't reflexively executing some procedure assumed appropriate for everything. And I'm grateful that the level of casualness and inattention that modern sport and gym climbing seem to have engendered was not a feature of our time.

All that said, the dynamic jump belay is absolutely the right tool for the job when there is nothing to hit and a pendulum fall happens (and on overhanging rock, every fall is a pendulum fall). The main reason (there are several) is conservation of angular momentum---lengthening the amount of rope has to decrease the magnitude of the velocity vector (well, the velocity component normal to the position vector) so your speed going into the wall is lower (unless possibly, as in the concave case, the wall comes out to meet you). Looking at the picture of the climb from the ground, I'm pretty convinced at this point that the belayer did indeed screw up.

My possibly fatal fall was on overhanging rock and so was an excellent candidate for the jump dynamic belay. If McCarthy had done that, I'd be typing this with my eyebrows, if at all.

Extra slack is not a soft catch. Extra slack out before the fall increases the factor.

…and increases the probability of what happened here, which is that the climber got his ankle caught AFTER FALLING. His positioning when he left the rock was OK. He wrapped is leg around the rope during the fall, which is more likely with more rope and more time.

That's not to say there's no place in good sport belaying for some extra slack (if you're not smaller than your climber), but it's dangerous to make it a primary way to give a soft catch.

A proper soft catch is a high level skill. You need to read the amount of friction between you and your climber, which is a function of the contact area of the rope with the rock, the angles, your weight and how fast you get it on the rope, the rock type, the rope condition, etc.

Belaying is a habit and most belayers will belay in the style that is safest for them most often. If your belayer isn't a sport climber it's unfair to expect them to give a great sport climbing belay. Again, wait for a day with your regular sport partner to do the riskiest climbs.

might have spared him the mishap to a point maybe entirely

A hair away from the onsight, I blew it. In fairness to the route and despite my self-spray at my failure, I blew it right where it got hard. As I did, I let the rope sneak behind my leg. Bad move, it’s a mistake I sometimes make. Problem is, sometimes it just happens, like, you have your foot here and it’s fine, move it a couple inches this way and suddenly it’s not, and in the moment of the move you f*#k up. I do, anyway, and from observing others I know I’m not alone. Most of us just don’t fall in that particular wrong moment. But I did.

a good belayer may well be able to mitigate the results

the direct belay for the leader off the anchor on multipitch routes is gaining acceptance.

I have a Petzl Meteor.

I would not use a munter to belay a leader either. Not much breaking power INMOP.