From what I can see in the video, I do not doubt that the artist created the digital work, at least in part, but I do doubt that he created this on the iPad. While the detail is fairly believable and the strokes appear to be moving, one of the posters on the linked site made a good point regarding screen recording on iPad. To the best of my knowledge, iOS does not provide capability to record onscreen actions in video format or still screenshots in rapid succession. This raises the important question of how the artist recorded his actions.
First, the technical considerations. You have to consider the angle of the device in relation to the angle of the wrist and eyes, as well as the camera. Then, you have to consider the elaborate setup to keep the camera tripod away from the artist so as to prevent bumping the tripod at any time during the capture. Also in consideration is the setup for the iPad in order to prevent any touching of the screen from moving the device even a tiny bit, which would be evident in such a playback. Of course, he could have edited any anomalies, but then the entire affair gets pulled into question regarding validity.
Another giveaway would be lighting. You would need an elaborate lighting setup to in order to maintain uniform lighting of the overall screencap area.
The final technical straw that breaks the camel's back is the fact that you never see him access the tool bars, ever.
Now, the artistic considerations. While we see the artist make stroke after stroke (at the playback speed, it is difficult to judge the validity of the stroke actions) there is the question of why some of the final actions resulted in a less than realistic freckles, moles and facial hair when compared to the rest of the piece. Was this to let the viewer know it is a painting, or did the artist pull a fast one, or, did simply use Painter's autopaint function and add to it? And in either case, why?
My conclusion is that he may have taken a single screenshot of Procreate from the web, or his iPad, and built his work in Photoshop or Painter. The only question I would have if this is true, why lie about doing it? Is he receiving some form of compensation from the creators of Procreate to push this video? I could be totally off my rocker here. The artist may have done the work. Regardless of method, the final product is impressive.
Sorry for the long-winded post. I tend to get too technical and veer way off course, meaning that I am probably wrong on all accounts here.