According to the IIA's Standards, if it has been more than five years since the last external assessment was conducted, the Internal audit activity must cease indicating that it operates in conformance with the Standards.
Regular external assessments are required at least once every five years to validate that an internal audit activity continues to operate in conformance with the Standards.
Institute of Internal Auditors (IIA) - International Professional Practices Framework (IPPF)

Board endorsement of the internal audit plan strengthens organizational independence by ensuring that internal audit activities align with governance priorities rather than management's interests, in line with IIA standards.

Having internal auditors rotate to other areas of the organization for non-audit assignments poses the greatest risk of compromising audit objectivity. This practice can lead to conflicts of interest and familiarity threats, as auditors may become too closely aligned with the operations of the areas they audit later, potentially impairing their impartiality and independent judgment.
IIA Standards on objectivity and independence; guidelines on auditor rotation and non-audit assignments.

The scenario where an internal audit manager fails to disclose a conflict of interest by not revealing that the process owner being audited is a relative is a clear violation of the integrity principle outlined in The IIA's Code of Ethics. Integrity demands that internal auditors disclose all material facts known to them that, if not disclosed, may distort the reporting of activities under review or conceal unlawful practices.
The IIA's Code of Ethics

This indicator suggests that the organization's ethics program might not be well-developed if the responsibility for communicating ethics compliance is decentralized to the level of employees' direct managers without broader oversight or structured programs. Effective ethics programs typically involve centralized communication strategies that ensure consistency and comprehensiveness across the organization.
Institute of Internal Auditors (IIA) - Guidance on Developing an Ethics Program