Final answer:
The lack of confidence in the client's ability to walk necessitates a referral for an assistive device to ensure safety and mobility.
Step-by-step explanation:
The finding that requires the nurse to obtain a referral from the health care provider for an assistive device is that the client does not demonstrate any confidence in their ability to walk. This indicates a potential risk for falls and mobility issues that could be mitigated with the proper assistive device such as a cane or walker. The nurse should prioritize this issue and communicate the need for a referral to the healthcare provider to ensure the client's safety and improve their mobility and independence at home.