As someone whose long had experience with scam developers, *cough* Gumdrops et al and having spoke to Mulan myself to help in some small capacity with the next update,
Honestly,
He's not a scammer.
What he is, is a dev that has bitten off way, way more than he could handle.
And yes, that is a criticism in itself, but it's one that stems from naivity in a project, and pretty much every dev at some point falls prey to it. (Unfortunately for Mulan, he has fell deeply into, and got burned).
It's certainly been a harsh lesson for him, and I think it's clearly taken a toll on his 'nerves' hence the reactions you're seeing.
But, moving forward he's promised not to commit to such work-loads and much smaller updates, it would pointless to release now prematurely with the update finally looming.
The most important thing is that a lesson was learned on being overly ambitious with limited means.
...
Speaking personally,
Development is not always smooth running, when I first came onto work on Taffy Tales, it was in an abysmal state, and the Patreon count reflected that.
It's very easy as a Dev to get creep scope, and I myself have fucked up with it.
I think personally, Mulan deserves a second chance after this update. If the same mistakes keep occurring, well, I won't say anything when you bring out the torches then, but till then...