I’m a serious anime fan, so I’m about 90% confident that this video is perfectly fine. I can’t speak Japanese, but I’ve picked up enough of the language from watching subtitled anime to recognize “oni-chan”, which is the familial form of address for a big brother and “senpai”, which is way to address someone of senior rank, often a student in a higher grade than oneself.
Otherwise, all I know for sure is that musician Yuri Umemoto is a true artist who can take a sample piece of dialogue and use it on an electric piano to create an oddly compelling composition. That’s most of anime anyway: oddly compelling.