Advice Needed!

1. When you're reading a confusing piece (i.e., with an ambiguous setting), at what point do you become frustrated or bored? I'm writing about an ordinary day, just twenty years after an honest-to-goodness, all-out nuclear war. I don't want to advertise it strictly as a "Check out this apocalyptic landscape!" kind of story, but I don't want to bury the lead either.

2. My MC has an intellectual disability known as Cri du Chat Syndrome, and she's mildly to moderately affected. What should I do in order to portray her both accurately and respectfully?

I'm a biiiiiit late in replying (I hope you don't mind), but I will say that it's really difficult to answer your first question concretely. It really depends on the piece for me, especially since there a lot of different causes of confusion. I'll cover the ones I run into most frequently:

If the confusion comes from the grammar or sentence structure, then my tolerance is pretty much nil. If there's more than one confusing sentence in a row (or one very long and meanderingly incoherent sentence), I'm out.

if the confusion comes from the dialogue, I'm a lot more tolerant, though it will annoy me, and if it turns out to be a consistent source of confusion, I'm out.

I'm most tolerant of confusion coming from the situation, especially if the story is being told from a character's limited viewpoint. If nothing gets resolved and things stay confusing though, I am not a happy reader.

As for your second question, I'd recommend doing as much research as possible first, not only on the disability but also its portrayals and the reception of those portrayals, and then asking more specific questions about the issues you need more clarification on. You'll get a lot more useful and applicable information that way, rather than blanket asking "how do I portray this disability?"