Double post update:
I can only presume he left the Terraria scene (and in turn, discord as well), I know he was getting upset with how his sprites were being judged by the TMODLoader discord.
He seems to still be active on steam thou which supports this.
I doubt he's ghosting us, just that he's done with Terraria in general.
That's really sad, if I knew beforehand I would have told him to not listen to the overly-critical spriters discord, those people are toxic.