I am very interested to know if you made progress with getting your blind cockatiel to eat fresh/whole foods.
I just adopted a blind Sun Conure yesterday. Her name is Peaches. She was surrendered to the rescue about a month ago. The rescue was not informed that the bird is blind. Perhaps the previous caretaker was unaware. We observed the bird, and noticed unusual behaviors, her continual head motion, but we did not realize she was blind until we took her to our avian vet for her initial check-up.
She is not clipped, and I will not clip her. She also has her naturally sharp, pointy toenails, which I will not clip or dull. I want her to have every natural resource to grip and balance, so she does not develop fears of falling and exploring. She has not tried to fly, even when transported around the house on my hand.
If she did start flying, I would consider a very minimal trimming of her wings.
Peaches eats seeds and "fine" (small) pellets. I am trying to get her to eat fresh vegetables and a little fruit, but I've only had her for a day. The rescue owner said Peaches was eating little or none of the fresh foods provided to her daily for the month she was there, favoring the seeds and pellets offered.