This code system https://fhir.hl7.org.uk/CodeSystem/UKCore-AdditionalPersonRelationshipRole defines the following codes:

CodeDisplay
AgentAgent of patient
GuardianGuardian of patient
PersonalPersonal relationship with the patient
PolygamousPartnerPolygamous Partner of patient
DependantDependant of patient
NonDependantNon Dependant of patient
ProxyContactProxy Contact for patient
ProxyCommunicationProxy Communication for patient
ProxyContactCommunicationProxy Contact and Communication for patient
CarerCarer of patient
NotSpecifiedNot Specified