EDITED
If she is running Big Sur 11.6.5 that is either a mis-read or Beta Software
softwareupdate --list-full-installers
Finding available software
Software Update found the following full installers:
* Title: macOS Monterey, Version: 12.2.1, Size: 12155426708K, Build: 21D62
* Title: macOS Monterey, Version: 12.2, Size: 12156325205K, Build: 21D49
* Title: macOS Monterey, Version: 12.1, Size: 12157035487K, Build: 21C52
* Title: macOS Monterey, Version: 12.0.1, Size: 12128428704K, Build: 21A559
* Title: macOS Big Sur, Version: 11.6.4, Size: 12439328867K, Build: 20G417
* Title: macOS Big Sur, Version: 11.6.3, Size: 12435122667K, Build: 20G415
* Title: macOS Big Sur, Version: 11.6.2, Size: 12433351292K, Build: 20G314
* Title: macOS Big Sur, Version: 11.6.1, Size: 12428472512K, Build: 20G224
* Title: macOS Big Sur, Version: 11.5.2, Size: 12440916552K, Build: 20G95