I don't know much about autism, but I would suspect that when dealing with any challenged groups you would want to use a design that is high-contrast with simple layout.
There is a lot of text to read on your homepage, and the menu on the left is fairly plain (which is good), but doesn't really stand out.
Also, using 3 lavenderish colors don't provide a contrast between different sections.
Why have multiple pages for registration and email? why not just have that on the home page?
When I create an account, it doesn't just give me access to the site, it makes me then login from the login page. This could be done better, when I create an account, just have it log me in.
Once logged in, I again have WAY too much text telling me about ?? i don't know because I can't be bothered to read so much. You should be able to visually display this info so that so much text isn't needed.
The first page again has a list of 9 options for the first question. I think that is way too much, it is overwhelming. And I think most people don't know what type of connection they have.
Then when you get into 'sex', it gets REALLY interesting...
Really?? there are 5 different types of sex?
anyway, I think you get the point.
I can't imagine somebody who has any disability having an easy time with this.
But as I said, I don't know much about autism, so maybe this is the type of information organization which makes sense to them.