Having a sibling with autism does not allow for the typical sibling rivalries or intimacies. It normally includes much loneliness for the sibling that is not in the spectrum and can lead to resentment and seclusion. Living in a home with siblings and autism is a definite challenge and it is a given that feelings will be hurt. Autism demands attention, so that sibling suffering with autism will receive more attention, good or bad, than the other children. The blame is not on the parents, they are doing the best they can, but in the end, siblings of autistic children lead different lives than typical children and sometimes resent that fact.
If the child in the spectrum is the oldest child siblings tend to feel more neglected that those that are older than the sibling with autism. It seems that if the sibling is high functioning, the feelings of neglect are lessened, but either scenario brings lack of attention to the younger child. Siblings and autism do not function well together if a younger child is affected either. The older sibling normally is asked to mature and take on responsibilities beyond their age. Becoming a care taker of a child with special needs is not a normal sibling function, so resentment will be forthcoming.
Many children in two parent families who have a sibling with autism feel closer to one parent and show hostility towards the parent who seems to cater to the autism. However, in single parent homes, the child who is not afflicted tends to be more protective of both the parent and the sibling. Each scenario is different of course, but siblings and autism is always a more one sided situation than a traditional sibling situation. There will be missed ball games and functions for the child who is not autistic just because of the needs of the sibling. Family functions can never be the same once autism is introduced, so siblings feel hurt.
Some siblings embrace the fact that they are not a child of special needs and many find careers that cater to helping people with special needs. But on the other hand, some lash out and are resentful of never having a sibling to tell secrets to or being able feel the sibling bond. Unfortunately, the scene of how autism and siblings will play out is as difficult to predict as the autism itself.