It is not that those with Asperger's cannot learn to interpret non verbal forms of communication it is more that they learn it in the same way as an adult tends to learn a foreign language. Instead of being something that is absorbed almost unconsciously, it is something that requires thought and practice and even then if something is even slightly different it won't be recognised. Again the empathy bit, identifying that other people are different , with different wants and knowledge is an idea, which even though they may have accepted it as true is still something that they usually have to consciously think about. Prioritisation of tasks tends to be a major problem as does taking an idea from the specific and applying it to a general situation. Sheer frustration can sometimes lead to what has been termed "a meltdown", an explosion of temper. Changes in routine can cause near panic, as they have to deal with something different and unfamiliar.

Try helping the child learn to approach situations and problems by taking a deep breath and instead of panicing at every thing that they don't know, to try to find just one thing that they recognise, to help them feel safe, before moving onto another bit they recognise. As someone else said it's not so much treatment as coping mechanisms and enough time and support that they feel safe until they are ready to deal with that one thing on their own.