description of these two attributes/functions should be corrected by changing 'role' to 'party' (see "Relationships in which this role takes part as source.")
description of 'reverse_relationship' should be changed to be clear that the refs are of the PARTY_RELATIONSHIP and not of the involved PARTYs (see comments above)
Looking at and thinking about this a bit more, I'd suggest deprecating reverse_relationships and noting that it could be computed in a service interface. We could even reference the service interface defined here: https://www.openehr.org/releases/SM/latest/docs/openehr_platform/openehr_platform.html#_demographic_package and add that function to it.