@chrisself, I moved your question to this discussion:
- Neuropathy post-Covid infection: Is there treatment that helps?: https://connect.mayoclinic.org/discussion/neuropathy-in-feet-post-covid/

Several members have reported having neuropathy post Covid infection. You're quite right that having neuropathy specifically in the tailbone is rare. Does she also have numbness in her extremities such as feet or hands?