Blood Parrot with Red Sores in Mouth

Hi,
I have a 5 year old Blood Parrot cichlid. He lives in a 190 gallon tank with lots of room, great/stable water, lots of aeration etc... A few months ago I started to notice sores inside of his mouth where his teeth are located. Since Blood Parrots cannot close their mouths, he always seemed to hold the food in his throat and crush it. Once these sores appeared, he still tried to eat but could no longer hold the food in place to crush it in his throat. Several weeks ago his poor appetite turned to no appetite and he acquired several secondary (I think) infections...hole in the head and fungus. I quarantined him and treated him for 1 1/2 weeks with API General cure. This helped the Hole in the Head so I put him back into the main tank. He is again trying desperately to eat but can hardly chew (and the red sores are still there). I have tried soaking the pellets so they are soft, various brands of flake food, live worms, frozen brine shrimp and blood worms...he can eat some but it is a struggle. Has anyone experienced a similar situation or have any advice on what to try from here? Thanks.