The holidays can be very stressful for a child with Autism, as decorations and different behaviors start to change the routine of the child. Hallowe'en can be very stressful because of the need to interact in order to participate.
But it doesn't have to be very stressful, as long as you have time to prepare your child. The folks at Rethink Autism have provided a free video for families to help their child prepare to wear a costume, go trick or treating, or even hand out candy if they want. The tips are grounded in the ABA methodology, and help by modifying the child's behavior gradually.
If you would like your child to participate, these tips may be helpful.