Admittedly, it's an hour long so I don't have the time to watch it. Skimming over it though, it looks like he may be writing C code, but compiling it via Microsofts C++ compiler. That's just my guess though. The code he's writing has some Cisms in it (And no C++isms, though it's basically just a 'Hello World'), but it's in a 'cpp' file and I presume VS is using a C++ compiler to do so.
C is for compatibility with older code, or code coming from other platforms.
At least in game development, you will usually use a sort of "C, with classes" approach. You use a C++ compiler and the class, and namespace keywords, but shun the rest of the C++ features like exceptions, virtual functions, and the STL for most of your code.
At that point, it's not really C and it's not really C++...
Very few people, even programmers, seem to know the difference. Some even claim to program in C/C++, which is about as meaningful as Java/Javascript or Java/C#.
All those Foogols look alike anyway.
ETA: I have no idea if we watched the same video. The commenting style in the first video on the top of the page was used in C decades before C++ existed, though, and since there was no actual code, it's impossible to tell if the person we're talking about will or will not confuse C with C++.