Nutrition plans are very individual and there's no set number of calories that will work for everyone. All factors should be considered when building a diet including overall activity level,age, height, weight, genetic advantages/disadvantages, training intensity and so on.
As a general rule she should eat less carbs on non-training days and the exact numbers and how much to drop will depend on her diet.
Most important thing is to find someone to help her that has the time to get to know her body in order to build something that will work. You mentioned that she might be starting with Dani in the near future so she'll surely set her on the right track.
I would love to give you a more useful answer but it's a lot more complex than people think, I monitor my clients every week and make changes based on how their body responds.