His behavior is pretty normal. He's talkative, been attempting to play with our other cat a bit, comes to us for attention and purrs, etc.
While I don't really put much stock in the vet's advice since it seems to be outdated, I do use them for tests and diagnostics and we've looked at pretty much everything that's been suggested either on here or by the vet. We did a superchem, CBC, and urine cultures about a month or so ago, got the acro and IAA tests, they just drew blood for a GI panel on Tuesday so we're waiting for those tests results, as well as them doing a physical example and not really finding anything out of the ordinary. I'm open to suggestions on what else we could get done beyond that that might help.