Why would you film your dog when its in obvious distress and not act earlier to cool him down.
A few years ago we had a Hereford Bull come staggering into the cowyard, we realised the problem and got a hose and buckets of water over him quickly, he soon returned to normality but if we had filmed him before the hosing he may well have died.
A timely warning, some dogs don't seem to know when to stop and take themselves into the shade, particularly energetic breeds like collies. However, I have to agree with Dobiegirl I am at a loss as to why the owner was filming instead of immersing the dog in cold water.