After Smokey ( A Timneh Grey) passed away after 28 years with Amy and I ( Blue Fronted Amazon) I adopted a 20-something year old Goffin from my then-girl friends brother DJ..not to bad mouth DJ,but him having 'too's for almost 30 years ( he also has Pooky,a 30 y.o. M2) and IMHO he doesn't care or want to know how to treat or take care of either of them. This may be not "appropriate" to post,so if a moderator wants to delete it,I will totally understand!
He also had Scooter,a U2,and housed him with Pooky. One day Scooter was feeling..ummm..."frisky" and tried to mount Pooky,a known female. When Pooky rejected Scooter's advances,Scooter lunged and bit Pooky,ripping her left eye right out of its socket!!

Pooky was rushed to her CAV with her eye hanging out and the CAV had to remove it.
When DJ returned home,he put Scooter in a small cage,took him outside and attached a HOSE from his car's tail pipe to the cage! Scooter passed away in a few minutes:15:
When I asked why for pete sake he just didnt rehome Scooter he said he was too "unpredictable and dangerous" I no longer associate myself with him.
ANYWAY..getting back to the subjest..I took Jonesy (the goffin) in since I have had two fid's all my life. Jonesy was on just a seed diet and an occasional piece of banana or grape. A "treat" was a piece of pizza crust or some sort of pasta/noodles/shells.
He didn't want to eat anything new no mater how hard I tried. It took Amy to convince him there were other food's around. One day I found him and Amy on Amy's playtop. Since Amy loves other birds,no mater what they are,I cautiously watched them interact and it seemed like Jonesy like Amy.
So I watched as Amy munched out of a bowl he has on his playtop as Jones looked on. AS if to say "c'mon..try it!" Amy moved aside and Jonesy helped himself to everything! walnut pieces..chunks of corn on cob..peppers..peas..he ate like he never had eaten before lol.
After that, just about anything that went into his own bowl he'd at least give it a try.
So..patients..and like Scott mentioned..make a fuss! let him see/hear you "enjoying" your share..he'll come around eventually. Good Luck and please keep us posted.
Just a side note here..I had to rehome the "beady eye'd so-and-so" ( nicname I gave him) because one day something snapped with him and he turned into a dr jecyl/mr hyde and one second he was so lovey and then the next he was ripping flesh off my hand making blood squirt everywhere and screaming from before sunrise to well after sunset.
Jim