My EEG was classified as normal without it having any implications for my autism diagnosis.
It is for sure possible that autistics may have a different EEG pattern, but it does not exist enough science yet to support it and so such use and measure of EEG does not exist at a serious clinical level but may be used serious in research. For that reason only the standard and valid use of EEG was taken into account when I was tested and that standard and valid test did not have any implication for my autism diagnosis.
At this point, it is not possible to confirm whether someone has an autism spectrum diagnosis with an EEG. I would encourage you to speak with your child's pediatrician to clarify the purpose of the EEG and to ask for a referral to a developmental psychologist or another professional who can do an evaluation of your child's skills and behavioral presentation. Only a trained professional who has experience evaluating individuals with autism can provide a valid diagnosis.