Sick Tiger Oscar

Where I work at they have a 6 year old Tiger Oscar in a 55 gallon tank. He is about 13 inches long also is the only fish in the tank. He has started in the last six weeks floating perpendicular in his tank, will not swim left or right at all. He also has a large lump on his left side that is about the size of half a golf ball. ALSO, he has holes in his head that I have since googled and learned are Hole Head? We have given him parasite food and  cleaned and treated his tank for parasites. He is now not eating and I do not know what to do about it. Any ideas?

[seattlemom2plus]

Was there an update on this?  How are your fish doing now?