I just got back. He was very loud all day (according to my family) and his behavior is very normal. He's sleeping further away from the heat lamp and he isn't puffed up at all. He's really acrobatic today, even hanging upside down by one leg. Poop looks better than it ever has since he got sick.
However I got very scared when I saw his head gently vibrating a few times, kind of like shivering but only his head. I looked up neurological symptoms in birds, particularly tremors, and they don't look like this though if anyone has some videos I would really appreciate them...Ever since I got him he's liked to rapidly wiggle his tongue, sometimes while making a purring sound, which would make his beak and head vibrate but I couldn't see his beak from that angle. He completely stopped once he became distracted by a toy and some treats so I'm not sure if that was the tongue thing or not. I'll keep an eye on him.