The reality of sharing custody or visitation privileges with a child's other parent is often very different from how you think it will be when you are negotiating a parenting plan. Often, life just gets in the way, and it is difficult to understand the right way to raise your child and also honor the other parent's rights and the agreement you made together. One common difficulty occurs when a child is feeling ill when it comes time to alternate custody with the other parent.
Truthfully, there is no simple answer to this question. There are many factors that go into the decision, such as the age of the child, the severity of the illness and the distance between the homes. Both you and the child's other parent have a primary responsibility to care for the child first and foremost in the matter, so if changing custody is truly not in the child's best interest, then it is possible that you should postpone the switch.