We built relations to be reciprocal. If am your Parent, you are my child. If you are my cousin, I am your cousin. If you are my guardian, I am your ward, etc. That worked well for that purpose and still does,
We later started adding attributes such as HIPAA authorized, Guardian, and Emergency Contact, etc. Those were done from the perspective of the client.
For example, assume a child "Mary" who is developmentally and physically disabled. She is likely to make her parent her Guardian and give her parent "Jim" HIPAA authorization to see her records or make her parent her emergency contact. Then when we look at the parent Jim's account and see that Guardian and HIPAA checkbox and emergency contact, to us, it seems obvious that people would understand that the disabled child, Mary, is not adult Jim's guardian or emergency contact - but that Jim is Mary's guardian and emergency contact. And most of our customers understand this.
But some people still do not understand because we show no relationship direction or further information. So, while just seeing a checkbox might be confusing for a small number of users not thinking about the client-nonclient relationships, even if we changed that to a one directional relationship, some of those users might still have the same issue of explaining that Jim is Mary's guardian and not vice-versa.