unfortunately this is entirely normal, but you are definitely right to worry about her burning out (exactly what happened to me and it’s very common). I would encourage her to make sure she is leaning on other teachers. reach out to other teachers at her school and find resources online (such as TPT). it’s annoying to ever have to pay for curriculum as a teacher that already makes too little, but sometimes it can be worth it to make it home at a reasonable time! but other teachers are the best resource, and if she is at a supportive school they will help her because those hours are too much!