Here is an interesting dilemma. An autistic teen got kicked out of a Catholic church because his disruptive behavior threatened other parishioners, the church's board said. (I'm not sure why the board made this decision and not the pastor, not that I oppose lay involvement, just find it interesting.) Supposedly he knocked some people down, spit on someone else, and urinated in the church, things his mother all denies. She points out, rightly, that we have an obligation to attend Mass on Sunday and she's trying to fulfill that obligation. Of course I suppose one could argue that developmentally he's below the age of reason and isn't bound by that requirement (would be interesting to see if he receives the Eucharist). They offered to set up a video feed for him in the basement but his mother says that's no better than watching it on television. She kind of has a point, although I've seen live Masses with video feeds. Interesting dilemmas.
I dunno, kicking other people and spitting on them is pretty extreme. It was the priest who affirmed that the boy was being violent; the mother says the priest is "exaggerating" but one wonders how to read that word without understanding "lying". Does she really mean to say that her son did not kick other children, spit on them, or urinate in the church?
It's true that we have an obligation to attend Mass, but we also have an obligation to love and respect our neighbors. Love is a two-way street. The parish tried to accommodate her, but she wasn't willing to take their offer. She needs to keep her son under control, and if she cannot or will not then she needs to leave him at home.
I have a cousin who is autistic. He is not violent, but serverly disabled. This is a hard question to deal with. If the pariahoners can tolerate it they should. I don't think there is anything necessarily in the young man's behavior given his condition that should preclude him from attending Mass if his fellow parishoners have the grace and determination to handle him and help him. I have found autistic kids to be like a very sharp knife, they cut both ways (for good and for bad).
As you point out, the young man's disability is a sufficiently serious reason to exempt him and a caretaker from the obligation to attend Sunday Mass, so the mother's argument sounds ill-informed.
If she has scruples about it, she could get an explicit dispensation from the Bishop. The family could attend Mass on a weekday, for example.
This dispute is starting to remind people of the overly-aggrieved parent in Natick who refused to accept reasonable accommodations for her daughter with celiac disease, and wanted to demand that her own choice of "solution" be implemented.