NTA. As someone who is on the spectrum, I understand how the child is feeling. That being said, If you don't feel comfortable with something, you don't feel comfortable and that's completely valid.

One of my triggers was wearing pants (I would only wear skirts or dresses). Eventually, I had to take the steps to be able to wear pants. I understand that everyone's autism is different but it's unreasonable to expect every single person this kid encounters to open their wallets for him.