As the parent of a child with autism, I can tell you there is no cure. Some claim to have success with a gluten free diet. Early intervention is the most you can do, and the earlier the better. The earlier an autistic child starts physical, occupational, and speech therapy, the better the outcome for the child.
If you have a child with autism, God bless you. Eventually you will feel that blessing. There will be a lot of heartbreaks and a lot of hard earned rewards.