The date and time a user was deactivated is not stored in the DB. Currently, you can only see the date and time when a User was Deactivated only by API 1.0 - GET /api/activities or through Dashboard>Activities
Customers want to filter Custom Views by User Deactivation Date (why?)
Add User deactivation date/time stored in the database and and available as info in the UI (including custom views).
Dev-less workaround provided:
manually store the date/time of activation in a user-level custom field (susceptible to human error)