by Acqua Alta.
Maybe he should check Vimeo - they have a domain level privacy option (when embedding videos):
https://vimeo.zendesk.com/hc/en-us/articles/224819527-Changing-the-privacy-settings-of-your-videos
https://vimeo.zendesk.com/hc/en-us/articles/224819527-Changing-the-privacy-settings-of-your-videos