In the YouTube video the process seems more a 50-50 acrylics-oil workflow but in the real time version you can see better how the acrylic part is extremely quick and sketchy meant only to support the brush work with the basic general blends.
If I have to put a label on this process I would say that's more a sketch & refine approach more than anything else, where colours are the main focus of every step!
Enjoy!