You may not be aware of, Temple Grandin, a high functioning autistic, I highly recommend you read her website and her accomplishments.
One of the things I found most remarkable, was her invention of the ‘hug box’ essentially a machine that squeezes, an autistic person cannot always ask another person for hugs, the social interaction being uncomfortable. Is your child like this?
It might be worth investigating a product called The Snug Vest. Essentially a vest that squeezes gently (and safely!) to simulate the feeling of a hug in a manner that does not become uncomfortable to the child, who can inflate it themselves giving them a feeling of control over their situation. Should they become uncomfortable, or feel themselves close to a panic attack or tantrum, they can squeeze, delivering a calming effect to the child.