The "non-denial denial" seems like a denial to me if you take him at his word that he is unable (presumably due to legal reasons) to comment about a specific project.
The first is there can be 'non-general' cases, and this could be one of them.
The second is a lot of 'standard digital tools' include AI features these days. A person can use generative AI without leaving photoshop.
Most likely, he did exactly that. Made a rough sketch and then achieved the final product either by just handing it to a model (which I'm guessing based on the maze) or he used gen AI tooling in his digital painting software to polish it into a finished painting.
It's not an accident that he's being so cagey and using exactly that verbiage.