Have you installed crouton? Check it out if not. Allows you to run a linux distro on a browser tab. Super useful.
If you really need a full-fledged Unix system (as I do), IMO it's best to run that on dedicated hardware and SSH in from a secure Chromebook. But I'm not sure what a student like the parent's daughter would gain from putting their Chromebook into developer mode, aside from a newfound susceptibility to malware.