I've been meaning to update this. The answer is bad, unfortunately. I let a couple days pass and he seemed fine but when I added him to the DT he basically swam into a hole in the rocks and never came out. 24 hours later he kind of blew by in the current mostly unable to swim and keep right, I got him back in the qt but it was too late. This one was really upsetting because I felt like it had been through all of the protocols to get rid of disease, I felt like I was relatively careful and got him through. He was eating, swimming, no signs of disease etc.
In the end my guess is that it's just a stress thing. I've heard a lot of people talking about fish having that 1000 yard stare in pet stores and that meaning they are not likely to survive. This fish ALWAYS had that and it worried me from the start, sometimes on tank changes he'd adopt a pipe and that made me feel good but usually he just kind of stared out of the tank. I guess I should have just let him chill in QT for another couple weeks in hopes of him adapting a more typical fish behavior pattern, but in my limited experience I've seen a lot of fish go from looking crappy in QT the entire time and then suddenly thriving once added to the DT. I thought, well he's eating, he's swimming fine, I was hoping rocks and caves and flow and stuff would knock him out of the aimless stare. The gramma is fine, at least.