Duck rehabilitation questions

[Rmalott]

Hey everyone!

So to make a long story short ish about 3 weeks ago our poor boy got botulism! He fought very hard and made it through the very rough 48 hrs and has been progressing. But we have stalled a bit in progress and I feel like maybe there is more we can do to help him.
He has pretty little control of his neck still he has some good days where he does great holding it up and then there are some bad days where it drops down and he moves it around in circles kind of. I am trying to figure out how to maybe make him a brace so maybe he can get a little muscle memory and control back. I know this is a long long road and that he may perhaps not recover from this stage, but my question is really two. 1. Is it worth it to build this? (We did it in the beginning when his head would fall backwards and it seemed to help him.) 2. What are some ideas for this? I want to perhaps have it hinge.
Thank you everyone!!!

 

[ChickenCanoe]

How old is the drake?
What are you feeding?

 

[Rmalott]

We rescued this drake, as it was wondering in the street, the vet we took him to estimated he is about a year and a half now. He typically eats the Purina pellets and we add niacin and vitamin mix to his water. But lately he will only eat peas, so we blend up the pellets so he kind of eats a soup and then drinks his water. He has been on doxycycline for about a week now. Still having issues with his head and not moving it in circles on the ground.