Hey patricya,
Which specific version of iOS 16 are you all running? Tested this on an iPhone 14 Pro Max running the latest version of iOS and the latest versions of both YouTube and Facebook app and when calling during a YouTube video, it did ring as expected, but it did not ring during the FaceBook video, which could potentially be a setting within that app. However, if you're running the latest software across the board, and you're being a different result, you may want to Get Support directly from Apple moving forward if the Facebook app doesn't have a setting related to silencing notifications during video play. If you're not sure where to check for that, work with Facebook Support.
Take care.