Arthur returns but gets put in mental facility
I am looking for a fanfic posted on AO3 or fanfiction.net that is told in the narration of an OC character. The character is a woman that works at a mental health facility and watches over Aurthur after he is sent there. Arthur returns but is sent to the facility because everyone thought he was crazy. The woman speculates on his arrival and story before Arthur gets a visitor (old Merlin). She watches the interaction between the two as Arthur realizes that his visitor is his old friend and they disappear leaving nothing behind but a walking stick.