Investigate & try the “Bs”
B vitamins show up as early as 1968 in the work of Linus Pauling in regards to autism. Dr Pauling called the approach "Orthomolecular psychiatry" which was basically finding the medical issues in "psychiatric disease" and giving what was missing, which lessened the symptoms of the disease. B vitamins are still the most commonly used medical treatment in autism.
Read more about the link to B vitamins and ASD
Summary of Dietary, Nutritional, and Medical Treatments for Autism by Dr James Adams.