Budgies do have tiny mouths don’t they?
What I found that helps with orally medicating budgies, is dampening the feathers around the beak area with a bit of water to slick the feathers down and away from the beak. Since budgies tend to bury their beak in facial feathers.
A trick for getting oral meds into the mouth of any parrot (parakeet) type bird, is to position your hand a bit toward the side/back area of the head, and slowly leak a drop at a time into the corner of the mouth where the beak meets the face. That way they can’t bite the syringe (since it’s coming from the back angle of the head, not straight on).
Remember, even with a smaller tip, when approached from the front angle they will bite it and make it hard to administer.
To make sure each drop is swallowed before giving the next; gently touch the top of the beak, which should result in beak movement and the need to swallow. Or else they will just store as much as they can in the mouth, only to shake it all out at the first opportunity.
Takes a little practice. Good luck with Kiwi
. Hope he’s all better soon!