2 weeks is getting towards serious.. i wish i knew more about discus to give better help but if you already tried epsom salt, pH, temps, different foods, could try adding new discus in there that will show them how to be normal, i did that w/other fish that were having difficult time adjusting...Tomorrow will be 2 weeks without eating. They seem to hide a lot too. Could it take even longer for the to get used to the tank?
if you look for other discus posts maybe ask another that has had similar experience bro. post pics if u can + hope to hear better results.