In order to schedule meeting on behalf of your boss, you don't need to look at their calendar or personal details of it. You can use FreeBusy to share their availability and schedule meeting on behalf of them.
Follow the guide to know how to schedule meeting on behalf of your colleague:
How to schedule a meeting on behalf of someone else?
Schedule meeting on behalf of your boss, manager or colleague easily without checking personal details of their calendar.
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Note: If schedule on behalf of option does not appear for you on Outlook Add-in or Chrome Extension, then follow this guide, and turn on team collaboration mode : How can I enable a setting that allows me to scheduling on behalf of my colleague?