So....I am not sure where to put this. But I want to write a character with Down Syndrome. The child is under a year and my MC adopts him because the people running the orphanage have given up at him ever getting a home because he has a disibility, and my MC has a bleeding heart.

Unfortunately, I know nothing about Down Syndrome at all. How do I write a character? Especially that young? Is there another disability that works better?

I don't have any knowledge to offer from my own experience, but George Will, a political columnist whom I generally admire, has written semi-regularly (when my local paper carried his column, and in the collected-columns books from the '90s) about his experiences raising a Down-syndrome son; those columns are likely to be scattered through his books or any online archive, but I think searching them out might prove worthwhile in your research for this character.

Find a youtube vlog about someone who has a down syndrome child ... people with disabilities/illness often offer a lot of information in their vlogs.

Moved to Character Development since this is a good topic about general character dev, not specific to the fantasy genre.

I love that you're asking this! Any time we can explore a forgotten, ignored, or underrepresented area in our fiction, I think it's a good thing.