Music from Family Sharing not syncing to iPhone

Re: Music from family sharing is not syncing to a family members phone

If you have an Apple Music Family Subscription, each family member gets their own Library, to which they can add whatever music they want on their device.

You may want to check that the family member has been added correctly:

How to: Add a family member to your shared subscriptions - Apple Support

You, or the family member, may want to check whether Apple Support's online article (link below) can help:

See what to do: If you can't find your family's shared apps and content - Apple Support