It sounds like she finally reached the end of her rope. It probably wasn't the first time the kid had done it to her or someone else and maybe nobody ever does anything because he's "special". Maybe a trip to the woodshed isn't a bad idea. Clearly nothing else is working.
Physical punishment for a 6 year old because he exhibits symptoms of his malady is not the answer. He should be placed somewhere where they are equipped to handle his kind of problems, Leaving him in with other kids is asking for trouble, he won't always be 6 years old and when he is older it will be even more of a problem to handle him.
“Maybe a trip to the woodshed isn’t a bad idea. Clearly nothing else is working.”
Which would teach nothing at all of any value to an autistic child.