Discrimination against children with disabilities

where do I start!!
So I'm a parent to a 5year old boy who has aspergers he's in main stream school at the moment..
My problem is everyday his head teacher is phoning me up over petty things saying he needs to be collected asap today it was because he refused to pick his coat up yesterday because he had an extra baguette at lunch very petty I know but there are children in that school who have assulted other children one being my daughter yet they don't phone there parents or send them home?? How is this fair she has now been isolating other children on the autism spectrum & blaming them for any problems they have in school not giving them the right help!!
Im setting up this petition in the hope either someone steps in to sort the school out or she is replaced ..