Navigator-Coach: has a better model of the medical system than community members.
Translator: has a better understanding of both languages of the medical personnel and patients.
Lifeguard: is better situated, and therefore more accessible and more aware of the patients' situations than the medical system can be.
None of these roles exist in the health care system. They have to be arranged ad hoc or suffer the consequences.
Doctors and hospitals do not and cannot have adequate models of all the possible relevant aspects of a single complex situated life much less all of the lives that they interact with. What is needed is a person of the same culture and neighborhood as the "Patient" who knows the patient well and who also has an adequate model of the medical culture ,its roles, and it's language. During Pursuing Perfection patients quickly identified this missing role, Clinical Care Specialist or Community Health Worker, as the most important needed addition to the current medical system.