Are family members info private?
Are iCloud family sharing plans data private for each member?
MacBook Pro 15″, macOS 10.15
Question marked as
See the following from Share iCloud+ with your family - Apple Support
When you share an iCloud+ subscription, everyone in the family group uses their own account. That way your photos, documents, and other information stay private, even though you're sharing access to the service. You simply share the features and space available in iCloud+ with your family members, so you only have one plan to manage.