I concur with the opinion that the giftedness complicates the presentation of the AS and the AS complicates the presentation of the giftedness.
It is a common mistake to believe that people with AS have no empathy. People with AS often have difficulty seeing things from another's perspective, but that doesn't mean that they lack empathy or feelings. They also often have difficulty assessing another person's mood or meaning from non-verbal cues, such as tone of voice or posture, and they may have difficulty expressing themselves appropriately through these modalities, but this doesn't mean that they don't have empathy, only that they may have difficulty reading and expressing emotions fluently in social settings. If his little sister gets hurt, and he knows she is hurt, it is perfectly normal for him to be upset even if he has AS. Gifted individuals with AS may have more capacity for self-analysis than the typical AS individual, but not necessarily more self-control, or more ability to modulate their emotional responses, which can complicate the process of getting an accurate diagnosis, and can be really frustrating for other family members, who may believe that because a child is bright and knows what correct behavior is, they should be able to control their responses.
AS causes problems with attention and executive functioning, which looks like "not caring", and being disorganized and "off task" frequently. AS often manifests with problems with balance and coordination, (Hans Asperger's original group of patients that he used to propose the syndrome were all "clumsy" boys) which can cause difficulty with both fine and gross motor tasks, and result in delayed, slow, or poorly-formed handwriting, difficulty learning to tie shoes, and/or delayed acquisition of skills like swimming and riding a bike. Sensory integration problems are a common clinical feature - certain kinds of foods, touch, clothing textures, lights, smells, or sounds may be irritating or intolerable to the AS individual, and may provoke a response that seems out of proportion to the stimulus, or they may seek out these stimuli in a way that seems out of proportion.
Anxiety and high levels of frustration are common in AS individuals. They are typically exerting a very high level of effort to cope with the demands of their environment on a nearly-constant basis, and may not understand why things are happening the way they are, even though it may look to a parent, teacher, or peer like they are not even trying do what they are supposed to, and their coping mechanisms for dealing with overwhelmimg stress (fidgeting, chewing things, tapping, rocking in chairs, etc.,) may get them into even more trouble.
It is very common for ordinary discipline measures, such as taking away privileges, star charts, time-out, etc., not to work with AS children the way they do with other children. It can be very stressful, and it can feel like your child is being deliberately oppositional and disrespectful. They almost certainly are not. Remember that they don't like being yelled at, criticized, or punished any more than you like yelling, criticizing, or punishing them, and they are not trying to provoke you. Accepting the diagnosis, getting appropriate OT and a "Sensory Diet" in place, and finding opportunities to praise what my son was doing right, even if it was tiny little baby steps in the right direction, has made a huge difference in the overall level of stress in the household. You might want to check out "The Nurtured Heart Approach".
I wish I had something more helpful to add. Know that you are not alone.
