If Shared Calendar Is Removed Events. If yes after the user who created the calendar was deleted permanently everyone cannot access the shared calendar including the 3 owners. For private calendars you can assign two types of access privileges to the people you invite.
You can remove participants from a shared private calendar or stop sharing the calendar at any time. Lets start with the first situation where there could be duplicate events which is with shared calendars. Delete an event you own.
Invite people to an event.
Empty the Deleted Items folder. That or a trash concept where deleted events go into a trash folder for a period of time before being permanently deleted. Some parameters and settings may be exclusive to one environment or the other. If the user is using the IMAP account then the deleted calendar events found in the trashed folder.