Sorry to hear about this
@Chiefmaster30. I don't have personal experience with fluconazole but I've not read any stories (before) of it affecting corals this way. You are already taking the steps I would - stop Flux, dim lights, GAC, WC.
Fish still not showing any stress is a good sign, but adds to the mystery. Totally guessing, but perhaps the fluconazole is killing/irritating some fungus or coral that is spewing toxin. Got an paly? I blame them for everything reflexively. I stub my toe, it is the fault of a paly covered rock I threw out 2 years ago. Stuff is still alive out there in my backyard.
The other angle is an introduced toxin. No melted heaters, cooked pumps, rusty magnets. Household aerosols, air fresheners, oven cleaners, solvents, VOCs, deodorants, pesticides, even dryer sheets. SUNSCREEN containing oxybenzone -- or any of the benzones. I pisssed off my frag tank with that stuff but not to this degree.
Good luck Chief.