The majority of child custody cases in this country have to do with neurotypical children, which can make it difficult for the parents of a child who doesn't fall into that category to develop a parenting plan that puts the child's needs first. Parents who have a child on the autism spectrum face some unique challenges when they have to deal with this.
One of the hallmarks of a child on the spectrum is that they depend heavily on routines to survive. Even small changes can have a huge impact on their ability to handle a situation. The issue that parents run into when they are trying to get the parenting plan set is that the court may downplay this need. Those who aren't familiar with the needs of a child who is on the spectrum may not have any idea what consequences can come from change.
Parents of neurotypical children tend to rely heavily on the adaptability of the children for things like transitioning from one home to the other. Unfortunately, children who are on the autism spectrum aren't able to adjust to the transitions. In order for them to be able to move between parents, they must have an entire routine built around that time.
Getting the child to the point where they are comfortable with the change and can switch between parents fluidly will take time, and it might not ever occur in some cases. Because of this, parents may have to try varying parenting time schedules to find out what works for the child.
Some children may need short periods of time with each parent so they don't depend too heavily on the routine at that home, but others may not be able to handle the frequent transitions. Sharing routines between homes and playing close attention to the child's behavior may provide clues about what parenting plan works best for the child.