Generally there are not intellectual delays with NS, but physical delays are not uncommon. Netherton's is a problem where the top layer of the skin, the stratum corneum, tends to slough off too early. This makes the waterproof barrier too thin, and the kids tend to be very red. The water loss takes heat along with it, so you have both dehydration and temperature control issues. The loss of heat means that the affected person has to use more calories for maintaining body temperature, which leaves less available for growing. A lot of kids with NS have a feeding tube early on to compensate.
I don't think there's a specific book for you. FIRST has several "Care and Feeding of Ichthyosis" type books
that talk about ichthyosis in general, genetics, and one for the schools, but aside from the individual information sheets here
, I don't think there is anything printed.
On Facebook, there's a Netherton's group (Netherton Syndrome Reseach Group) as well as a few general ichthyosis groups, Friends of Ichthyosis and Ichthyosis Mommy Spot.
carlyfindlay.blogspot.com is an adult blogger with NS that you might like. And my blog is general ichthyosis, and it's linked below.
If you can, try to get to one of the regional conferences this summer (Dallas, NYC, San Jose Ca, Kansas City, Cincinnati), or even better, to the national conference next June in Indianapolis. And contact FIRST directly so they can put you in touch with your local regional people.