How does the family member access the shared files?

The members have enabled sharing on their accounts : Share purchased content with Family Sharing - Apple Support ? If they have, to download a different member's purchases they need to go to the Purchased tab in the iTunes Store / App Store / iBooks app, select the account that they want to download from, and then select the item

Items no longer in the store won't show for redownloading, neither will items bought from a different country's store - not items that the member has hidden from the cloud (Hide and unhide iTunes Store, App Store, or iBooks Store purchases - Apple Support)