You can try to restore an automatic backup of her database under settings > backup and restore, this will restore the metadata, but the actual files are probably lost. Hopefully you have copies of these files elsewhere.
As you've just learnt, it's really important to make regular backups of your personal data, in Mobilesheets, or in any other program.
As you've just learnt, it's really important to make regular backups of your personal data, in Mobilesheets, or in any other program.