I've come across this situation quite a lot at both primary and secondary level. The other children behave as one would expect (ie part of 'normal' development) and the child with Asperger's is trying to cope with this. Neither side understands each other. But here, it is the parent who seems to be the problem. All you can do is stand your ground and try to predict how the mother will respond to any situations that arise. Always be ready to give an account of how you dealt with it or will deal with it and stick to your guns. You have to be unequivical because this kind of parent will leap on any evidence that you are in accord with her view of the world: 'Oh, but Ms XXXX said that the other children had...blah...blah.' Been there.