I thought that too but I looked up the video and all the descriptions say that the owner threw the stick, the dog chased it, got stuck in the current, and the other dog saved it from drowning. Then the owner posted the video to youtube
I couldn't find that exact video on youtube but I found a different video from the owner at the same location...there is indeed a safe little pool after the rapids. The dog wasn't in any real danger
It turned out that the caption is fake and that this is a place where the owner walks them daily. Apparently there's no real danger for the dogs and they're used to play there :)
Damn, they cut off the last part where the dog that saved the other dog goes 'long live the king on the other dog and pushes him off while taking the stick
He's not helping because it's a trick these dogs figured out on their own and are playing.