I know from experience you will not regret dropping the money to vet Stevie. I can sleep better at night knowing we have my parrots blood count, levels and numbers, information that will clue the doctor in knowing if there is a problem developing. Every year I bring in my parrots to have a well bird checkup and blood draw. This helps keep on top of things and can get signals if disease is starting to develop. Diego died of a stroke. He had heart disease and I didn't know it. I struggled with my Noble macaw's heart disease for almost two years before a heart attack finally took him. I will never neglect the well bird checkup and blood draw again. The first appointment will be the most expensive but after that, depending on the results of the lab work will dictate future care.
I also feel a kinship with you as my heat went out to you when you were having your problems with Stevie. All I knew is that it didn't have to be that way with your Illiger's macaw and that you were hurting over the issues. If you ever want to chat about Illiger's macaws and have questions go ahead and PM me. I look forward to more video's and posts about Stevie.