The cougar that is chasing him is not a female with cubs as can be seen from a side view at frame 5:40. It has no dugs (teets) which should show under its belly if it is nursing cubs. Back at the beginning it does look like a large cub turns off the road to the left and then another grown cougar appears coming up the road at frame 0:10. Another thing that does not fit is two adult cougars together unless it is a female in heat and that is why there are two adults together. Breeding is the only reason a male cougar is with a female. Males are solitary and take no part in the raising of cubs. That behavior of the cougar chasing the guy is Bizarre though, regardless of why it is doing it! I’d say the guy was pretty lucky the way it all ended.
I’ve only had one close encounter with a cougar and that was a young adult in my hay shed I may have posted about a few years back. That one was about 10 feet away and sitting on top of my hay bales when I walked in, but as soon as I moved a little farther into the shed it took the opportunity to escape rather than attack. I’m sure it was as surprised as I was at that encounter. LOL!!!