1. It is essential to first delete all tables associated with the user via ArcGIS Pro.
2. Only then should you delete the user in SQL Server.
If you delete the user directly in SQL Server, certain data entries may remain in the enterprise system tables; these entries will appear in the Catalog but cannot be deleted from there.
ArcGIS Pro does not provide a tool for deleting enterprise users in SQL Server. ESRI documentation also offers no instructions on the correct procedure for deleting a user in SQL Server. You may find advice online suggesting that the user be deleted directly in SQL Server—but doing so can lead to the problems mentioned above.
