What action must a commanding officer take when a physician reports an inmate's illness as critical?

When a physician reports an inmate's illness as critical, it is imperative for the commanding officer to notify the inmate's relative or friend. This decision is rooted in the ethical responsibility to keep the inmate’s loved ones informed about serious health matters that could impact their well-being. In cases of critical illness, family or friends often play a vital role in providing emotional support and may need to be involved in decisions regarding the inmate's care.

Additionally, keeping relatives updated on the inmate's condition is part of maintaining transparency and upholding the humane treatment of inmates. This notification helps to ensure that the family is aware of the situation and can take necessary actions, such as making arrangements for support or legal representation if needed.

The options of notifying the inmate’s attorney or the director of the facility, while important in other contexts, do not prioritize the immediate communication with family during a medical crisis. The notification to a prison guard is similarly less relevant because the guard's role is not focused on family communication or the care of the inmate. Thus, conveying critical medical information to relatives or friends is the most appropriate course of action in this scenario.