I think congregations cope better when the child looks disabled they struggle when the disability is less tangible. In all my time as a witness I never heard a local needs talk or any talk about how to connect with someone with ASD or how to show compassion and tolerance in meetings. It is as if in Watchtower world these people do not exist. In assemblies provision is made for the elderly, blind, deaf and physically impaired but no provision is made for ASD children. In the shepherding the flock book I am not aware of a single entry on autism or shepherding families with special needs.
At assemblies my son got distressed when there was feedback on the speakers, when the sun got in his eyes, when he was cramped. He found being outside all day unbearable. It was ok at first because when he was very small there was mothers and babies and then later we were able to retreat to the car if necessary. But the last year the society said there would be no car parking for anyone other than disabled and everyone had to go by coach which is fine if everyone is physically able but a disaster if you have a child on the autistic spectrum who may have a meltdown and need to leave at any time.
I think that because they cannot contribute to the tasks then they are not included in the plans or preparation. There is no place for them long term in the organisation unless they are very high functioning and have their religion as one of their obsessions.