Australian author William Alan (known as Alan) Marshall said that before he was born, his father said that if he had a son, he would make him a runner and bushman. When Alan Marshall was a child, he contracted polio.
Sometimes, the only expectations that a parent may have to adjust is that the child they hope will be a sportsperson might instead become an academic or an engineer or even a doctor.
I remember a ridiculous doctor writing an equally ridiculous article claiming that a person's mortgage could be making them sick and the content of the article was misleading and off on a tangent to say the least. If this doctor had meant that a parent wanted their child to attend a particular school, and to do so they had to live in the catchment area, and that meant they had to move to a more expensive area, that's one thing. Instead, this doctor ranted about how parents were bringing their kids to him and asking him to fix their anxiety and he would ask them to describe a typical day and that would involve getting up early, the husband was working long hours and the wife would have to get the kids off to school but not before ensuring they had their breakfast and a school lunch packed and then afternoons of driving the kids to swimming training and football practice and music lessons and what have you, to which, I would say, "No, the issue is not the mortgage, the issue is kids being overscheduled." I say, if a kid wants to go to a particular school, that's one thing, if a kid wants to play sport or music, that's one thing, if, however, the parents are trying to live their lives through their kids, that's the real issue.
An autistic kid may not want to play age matched sport. An autistic kid may not want to play sport. I have known kids who've HATED cricket or football and who go and play every Saturday not because they want to but because their parents want them to. If you want your autistic child to play soccer but they'd rather play chess, well, you have to adjust your expectations. But just because a person is diagnosed as autistic doesn't mean that you should have low expectations.
If someone tells me that they have an autistic child, I ask them what their interest or talent is.
I even remember my father's brother saying that another of my father's siblings had a grandchild diagnosed as autistic and I said to him, "Well, there's an autistic person sitting at the table. Me." And not to mourn but to celebrate.