Hello, I'm Dr. Bob.
I apologize for the length of time this reply has taken to get back to you, I've been offline, and there just aren't many bird-knowledgeable veterinarians online. I'm very sorry to read of Onie's condition, and I understand your concern.
There are a number of possible causes for the condition you've described, most of which would quite likely be treatable with a proper diagnosis. Foreign material, hard seeds and infections can all cause problems in Onie's crop. If he wanders free, unless watched constantly, he may have picked up and swallowed something like thread, a bit of material, a button or almost anything else. This could be relatively straightforward to correct. Bacterial, fungal and viral diseases can also cause the signs he's showing. once diagnosed, most of these can be successfully treated.
Do get him to an avian veterinarian as soon as you can, as problems like this can worsen with time, lessening the chances of a good outcome for him. You can locate those avian veterinarians closest your home by going online to www.aav.org/search, or searching for "avian veterinarians + (the name of your state or nearest large city)". If you should have any further questions, please let me know.
Kind regards, *****