I think the guy is straight up using the money to learn how to make games better. Like he released a dev log where he basically explained his reasoning, build, update, and refining process for the game mechanics, and all of them are extremely refined and seemingly entirely original. Now, I'm gonna go out on a limb and say, the guys knew some code before, but mostly just learned how to use the game making software, and didn't know much about making models, coding effects or making UI, or even really much about making game mechanics. He probably also is learning more and more about posing and custom animations and the sort. The reason being that not only did the dev log go into how much he's improved, but between the scenes and quality of animation and and mechanic in the sneak peeks and Christmas and Halloween event, and the game from 4 years ago; there is a lightyear jump in quality. Keep in mind this is just one guy working alone.
From what I see, there are custom animations, custom UI element, custom models, custom animation, custom game systems, custom game mechanics, and custom subsystems to interconnect all of them alongside highly improved and custom made animations and creative writing and storytelling. Before the game consisted purely of premade assets, models, animations, and UI but with a little spice of custom poses in some cutscenes ever now and then. Now, he could just make the game using that old style before the improvement in quality, and the game might even be done by now. But instead he's cooking up a higher quality product, and it's really up to him to decide what he's going to make as a creator motivated by his ambition alone.
On the other hand, it is in fact mildy scummy to basically go radio silent on making updates on Patreon and itch and here, and mostly only updating and informing on his discord and Trello while receiving tons of money monthly, and essentially instead of returning gameplay, using the money to learn how to make a better game.
While it is technically game development in the sense that it is pointed toward making the game in the end, it technically isn't making the game he is being paid to make. However this is only in the sense that people expect him to make the game with their money, rather than subscribe an investment into making a game after learning how to make a better one.
All in all, it cost me nothing to wait to for a better game to the quality he wants to make since I'm not subscribed, and I'd rather play a better game than a thrown together one. Also, assuming he goes on to live life after making the game, he will have best spent his time learning game dev skills rather than just throwing a game together.
But that doesn't stop the reality where he is in fact basically, by lack of being forthright getting people to pay for his game dev education, when they think they're paying him to make the game itself.
