Diagnostic labels are just that, a label and depending on the competency of the clinicians they can vary for an individual. I have found that PDD-nos is often given by clinicians who do not have the high level of competency it takes to accurately evaluate a child. In the end with a few exceptions it is all about having parts of the Autism genetic set.
The 3 core characteristics are almost always what needs to be understood and supported first. Sensory differentials need to be cataloged and adapted for and worked on to the extent that it does not create damaging anxiety. Social skills are generally the next area which require, first an acceptance that the child does not have innate societal social skills innately and that they need to be taught intellectually and generalized like any other curriculum so that the child can have a complete a set of intellectual compensatory skills as possible. If the family or social environment do not understand this limitation, and expect neurotypical abilities and reactions, again it can generate exceptionally damaging anxiety, to the point where gross clinical co morbidities like OCD, ODD, Bi-polar, anxiety disorder and so forth occur. Executive function is the 3rd characteristic. For most spectrum kids it is most obvious in difficulty with linear processing, which is the structure that is used in schools to teach neurotypical students. spectrum children's system is non linear (image based).
Anxiety and its manifestations are always the best gauge of how well a spectrum child is adapting the gross discrimination that exist in living in a "world" designed for a completely different genetic evolutionally imperatives and abilities.
It is often missed that these genetics come along with some amazing gifts, once you understand and get the anxiety production issues manages and provide appropriate supports.
They need to be learning the compensatory skills that I described above, within the limit of not generating damaging anxiety. I would suggest for mom and the extended family to become familiar with the floor time model and begin to implement it.
Here is a link
http://www.icdl.com/dirFloortime/overview/index.shtml
Sitting in front of the TV is not necessarily a bad thing as long as the content had both strong intellectual and appropriate social modeling content since it is one of the most effective ways to manage anxiety and is the child's natural mode of receiving information. It cannot be a substitute for as intensive a program for working on the 3 primary characteristics and teaching skills and adaptations for them.
Bookwormde