Assalamu Alaykum Rabia and welcom to the Forum!
LR is definitely suitable for Down Syndrom, you can just search the forum and find tons of threads about it! There is also a blog you may find useful by Kmum, a Brillkids member, you can check it out here:
http://downsyndromeupupupandaway.blogspot.com/I also did a review for LR here:
http://babyalbab.blogspot.com/2011/10/product-review-brillkids-little-reader.htmlIf you haven't downloaded the trial version yet, please do so you can get a feel of how LR works:
http://www.brillkids.com/free-trial.phpAlso, if you are teaching Arabic, you will find lots of files in the free download section here:
http://forum.brillkids.com/downloads/?cat=94 . I am also working on more LR files (vocabulary, poetry, phonics & Islamic knowledge) and will be uploading them very soon in sha' Allah.
You may also read a book written by Glenn Doman that is very informative, you can order it here if you can't find it at your local library:
http://www.amazon.com/What-About-Your-Brain-injured-Child/dp/0757001866