Earlier quoted context omitted.
> sounds like a privileged position that is unrealistic for many teachers Well sure, he lives in Australia which has much, much better working conditions than the USA. It sounds like your girlfriend is being taken advantage of and working in a situation that is not to her benefit. In which case she needs to start looking for a new job!
I wouldn't say she's being taken advantage of. This is a city school in a depressed area, everyone is overwhelmed (she has several hundred students across her classes), and working with near-zero budgets. There just isn't work available within a reasonable commute distance. She'd have to move if she wanted better conditions.
There you go. Do what it takes to improve your work-life. I moved from one perfectly good First World country to another, because I wanted a different life. It was difficult and took a long time, but it was absolutely worth it.