Thank you, pricklymaster!
From your screenshot of her device, it doesn't look like she's part of your family group. Does her Apple ID still show in your family? Also, can you double check that the Apple ID she is signed into with her device, is the same Apple ID in your family group? We ask because from what it looks like, it appears that it is giving her the options to set up her own family sharing group.
If that is not the case, we recommend reaching out to Apple Support directly so they can look into this further for you. You can reach them by following the below link.
Contact - Official Apple Support
Have a great day.