Final answer:
The nurse should instruct the parents to establish strict routines and avoid any changes in the environment for home care of a child with autism spectrum disorder. Consistent routines can help reduce anxiety and provide stability for the child.
Step-by-step explanation:
The nurse should include the instruction to establish strict routines and avoid any changes in the environment when providing home care for a child with autism spectrum disorder (ASD). Children with ASD often benefit from predictable routines and familiarity in their environment, as it can help reduce anxiety and provide a sense of stability. By establishing consistent routines, the child's daily activities and schedule become more structured, which can be comforting for the child.