The act of one tortoise helping out another doesn't seem to be a common occurrence in nature. One individual at All About Wildlife (AAW) has a suggestion for why something like this might happen. Once the tortoise rights the other, you will notice that he continues to follow her. While I am not sure of the sexes of the tortoises, they say on AAW that females are usually larger. Since the one flipped over appears to be the larger of the two, it may be the female. It's possible the male did the flipping, and the male may be interested in mating with the female. The timing of the upload also suggests this as the video was posted in November, and mating season for this species typically goes from September to November. 

What is really going on? Only the tortoises themselves really know for sure, but the act is still inspiring when seen in the video. Share your thoughts about what is happening in the comments below.