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.
I and 2nd this, he's still alive, but had to put down terraria due to heavy IRL issues.Very important news: PhilBill is still alive. He's not able to work on this mod due to life being busy, but he might be able to come back in the future. Ik it sounds weird coming from me because I'm just a random person, but I was rather good friend with Phil, and there's a screenshot proving this statement in the mod's discord.