I'm curious as to how you came to be involved in this.
For one thing, if the patient is in assisted living, they're no longer your patient, but a resident of the ALF. How was your supervisor able to "schedule" an appointment for them with the ALF nurse?
Secondly, how do you know that the resident wasn't seen by the facility nurse? I've got some folks in my building who'd swear they've never even met me, yet I've been in and out of their apartments many times. It may simply be that the resident WAS assessed and the nurse didn't bother to call you and the family to inform you of her findings.
Thirdly, that ALF nurse may be responsible for several buildings, or she may work only a few hours a week in that particular facility. ALFs are notorious for not wanting to spend money on nurses! Also, the nurse may have been sick that day, or, Heaven forbid, she may have simply forgotten.
Finally: Just because someone sees the ALF nurse behind a desk, it does not mean she isn't doing anything. Most ALF nurses are managers, not direct-care providers, and we do not have the time to do "rounds" on 80 or 90 residents each day. I will say that when an acute issue is reported to us, we usually make a personal visit to assess the resident; otherwise, we do a LOT of paperwork, schedule and train staff, hire and fire, delegate tasks of nursing care, act as facility administrator whenever he or she is out, and even give tours of the facility.
Of course, there is always the possibility that the nurse was indeed negligent in failing to see this resident. But one should never assume that based on a grieving family member's say-so.