If you don't want to give a staff member full permission to see all customers, you can assign a staff member as an administrator to one or more specific customers.

Go to the customer's profile in the administration area and click on the Customer Admins tab.

Click the assign admin button and choose, the member(s) you want to assign as admins to this specific client.

Register modifications.

The member(s) you assigned will now be able to view this client with the Client menu item without having the VIEW client permission.