Hi, discus need two main things. Very very clean water, and a temp at 80-85 degrees. You must do weekly water changes with discus and make sure they are not in a crowded tank with aggressive tank mates.
The ideal setting for them is companions of their own kind, a nice school of rummynose tetras or neon tetras also will bring them out of being shy. Cory cats are also very nice to add with them.
A nice planted tank with driftwood, live plants is also a favorite of theirs.
What size of tank do you have?
The thing to keep in mind is that one adult discus needs 10 gals water. So if you say had a 55 gal I would put no more than 3-5 in that tank. They get to quite a size.
I have "one" discus in my 25 gal, many say that they do better in 5-6 but if your tank is like mine I would only be able to keep 2. Put two in there and you have problems. I used to breed angels on a large scale, if you want to breed and need a pair the 25 gal is okay for them. But if you want a nice community tank like mine is 2 of them will just cause major fighting (learned from experience).
So in my 25 gal I have one beautiful discus, one angel and some small schooling fish. I also have my bristlenose and a couple of cory cats.
In your case I would definatley get your tank under control as to what caused the cloudy eyes. Watch your remaining discus for any signs of illness. It will be just fine by itself till you find out what is going on.
Do your weekly water changes and vacum that gravel well. All sorts of things get trapped in there and foul the water fast.
If you could mention the size of your tank, what other fish are in there that would help a bit.
Sorry to hear about your loss, these are truly beautiful fish. Keep us posted
Season's Greetings....bugsy
