BTW, the artist displayed us the screenshots and sketches done in Procreate, so he genuinely has drawn those panels. And you can clearly see it (as I did) if you look at the picture: lines and color fills are genuine and smooth. Not a photoshop copied-pasted for sure.
Yes, he might have used references and copied those ideas (drawn the same frame layouts exactly), but the artworks were done in hand.
It might affect his reputation though, so I'd rather advise artists to use the references carefully.