I've seen this a couple of times now and I agree; it is hard to watch.
I don't know if jiu jitsu would have helped or not. It might have. Perhaps not. I'd like to think so and I very much hope she and her family can get to the Academy. That's a wonderful offer from the Gracies. I think more than the techniques, JJ gives you a mindset. It teaches you that a determined opponent can destroy you -- and sometimes there is nothing you can do about it in the moment. The ego gets destroyed in training because you learn just how truly difficult it is to actually defend yourself against a resisting opponent.
More than anything this video serves as a counterpoint to all of the bullshido videos out there showing you how to "defend yourself". I saw one shortly after Sandy Hook of some local instructors showing teachers disarming tactics. It was laughable. This giant dude in a padded suit just standing there while everybody yells HIYA! and takes his gun. Try your HIYA! technique against the guy in this video. The plain fact is, the vast majority of people are wholly unprepared for the speed and violence of a genuine attack. Everyone likes to talk about "what I would do..." in a situation. What most people would do is get the ever loving shit beat out of them before they had any idea what was going on.
One of the great lessons of BJJ is that NOTHING comes without practice -- and lots of it. In the heat of the moment you need to react and react appropriately. The only way to do that is to train the muscle memory. That only comes with real, live reps. At least in jiu jitsu you face a resisting opponent unlike so many other arts. But even then, we aren't trying to really hurt or kill each other. With rare exception, we tend to like our training partners and want to come back again tomorrow. We train hard, but we do so with consideration for each other.
Outside of the military (and even then, only a fraction of it), police, and professional security folks, very few people ever train for a life-or-death confrontation that is similar to this situation. It's a lesson no one should have to learn the hard way.