Welcome to you and your little Goffins!
I'm guessing he is a bit under one year old? Are you in contact with the breeder? Has your little guy seen an avian certified vet? Not just any vet, but one with special training for birds. Many with "exotic" experience know little more than the traditional dog/cat vet.
As plumsmum2005 posted, Goffins are *not* highly food motivated. However they do have some favorites, and once you identify something enjoyable it can serve as the appetizer for greater variety. Some of the foods mine especially enjoy are peas, garbanzo beans, pinto beans, edamame in the shell, cooked yams and sweet potatoes, apple, orange, pear, melon and especially the seeds, banana, pomegranate seeds, corn (small quantities) various grains such as quinoa and oats. Cooked cereals such as oat meal and oat bran, Malt O Meal are enjoyed at room temperature. Cooked whole grain spiral noodles are a favorite. Small pieces of dense whole grain breads as a treat.
Another consideration is that Goffins are flock eaters. When one begins the others follow. He sees you as a flock member, so prepare a bowl for your Goffin and one for you. Begin to eat, bob your head up and down, make "Mmmmmm" sounds as if enjoying. You'd be surprised the impact this has and he may join. Try giving him a piece with your finger and encourage nibbling. (just not any food from your mouth!)
Finally, your bird has not finished weaning properly and never learned the purpose of food. There will be a transition between syringe feeding and a healthier enjoyment of solid food. Let us know how things go, but I would really advise a visit to a proper vet just to rule out any issues!
