I am unable to view parent calendar in default calendar
If the default calendar is the school calendar it could be that the Parent calendar is not subscribed to this default one.
Go to Calendars > Select School Calendar (Staff) > Select Preferences (Top right) > Subscriptions > You will notice that the Parent Calendar does not even appear as an option. This is because the Parent Calendar is set to private.
Go to Calendars > Select Parent Calendar -> Select Preferences > Set View Privileges to Shared: All logged in users -> Save.
Go to Calendars -> Select School Calendar (Staff) > Select Preferences > Subscriptions. You will notice that the Parent Calendar will now appear. Select it and select Save. The Parent Calendar should now show on your Default Calendar