The first (and simplest) thing to try if something isn’t working right is to restart your and her Apple Watch and its paired iPhone. If necessary (device not responding), try a forced restart. Both methods can be found here:
How to restart your Apple Watch - Apple Support
Restart your iPhone - Apple Support
She might also try turning fall detection off when restarting the watch and then turning it back on afterwards.
If that doesn't help, the next steps would be to unpair and pair your and her watch again and restore from the backup just created. This should result in no loss of data. It deletes all temp and corrupted files and re-indexes the file system.
Unpair and erase your Apple Watch - Apple Support
Set up your Apple Watch - Apple Support