http://arstechnica.com/apple/2014/03/snow-leopard-updates-ar...
With Apple stuff it seems like it's best to stay within 2 revisions of the latest OS, especially since they've moved to shorter release cycles (yearly).
If only Alt+Tab worked on windows rather than apps, like in MS OSs, or even if there was a taskbar-style way to switch windows, she'd have so many fewer problems...
CMD-~ cycles through windows. hold-click or right-click on a Dock icon displays a list of Windows associated with the application
Alternatvely, perhaps she might like Exposé (try F3)
Apart from that, even on 10.6, you can do the update of Bash yourself, you're not required to use the Apple patch: https://github.com/ido/macosx-bash-92-shellshock-patched
This has been compiled on Mavericks, it may run on 10.6. If not, you may need to install Xcode
This may not help for your case, but it may interest keyboard shortcut junkies.
When I was getting used to the "interesting" way OS X handles CMD+TAB versus Windows' ALT+TAB, I was also frustrated at the app-vs-window issue.
I eventually figured out this workaround, which sounds complicated but is now muscle memory:
1. Hold CMD. (Don't let go until I say so.)
2. Press TAB once.
3. Tap the arrow keys (LEFT/RIGHT) to go to the correct application, e.g. Chrome.
4. When you have the correct application selected, press DOWN. (You can release CMD now.)
5. This will display all of the open windows for this application (same as "4 finger swipe down" gesture). You can use the arrow keys to navigate this. An extremely subtle blue halo is displayed around the selected window. Press RETURN to select.