Please add my thanks to Scurby for posting the video. It is very hard to react to an emergency situation and for one I think the father reacted very well when taking into account the experience and the situation.
I won't repeat all that has been said, but would like to point out something that is bothering me a lot in many of the comments. Please excuse me if this has been said before, but I didn't see it.
Many people are saying "if caught in a down current, get away from the wall". I'd be interesting if someone could enlighten me because to me, that sounds like bad advice.
Here is the way I see it: When you are trying to swim against a current, you get to the bottom. Why?
1-Because of the friction created by the bottom, that's where the current is the less powerfull.
2-You got something to hold on into if the current is too strong to swim against. You can also crawl your way up the current.
I believe the same is true for a wall when in a down current: the current is less powerfull next to the wall, and you can hold on to it and either wait for the current to be less strong or follow the wall to get out of the current horizontally.
What if you go over the blue and the current isn't lower? You could get pretty deep very fast, with nothing to stop you.