I have a family sharing plan and my family member is not able to share my storage plan???
I have a family sharing storage plan but my family member can’t use more storage. Why?
iPad 2, iOS 9
Did you perform the steps in the "Share iCloud+ with everyone in your family" section of Share iCloud+ with your family - Apple Support ?
and, if your family member previously had more than the free 5GB of storage, did they perform the steps in the "Switch from your iCloud+ plan to your family plan" section of that same support article?