If her structure is all over the place is she starting with an essay plan? I'm studying a psychology degree so lots and lots of essays. I always start with a plan. This is my process:
Take the title and underline any instruction words in red eg explore, discuss, critique. In green underline any specifics to refer to eg chapter of the book, theme, whatever, this makes sure you are thinking about the question and sticking to its parameters. If she doesn't understand the question or isn't sure what she's going to say in response, then now is a good time to start brainstorming. But this is more about structure than answering the question as such.
So assuming I have a vague answer in mind, then I have a look at how many words I should be writing, if there is a limit. As a rough idea, between 10 and 15% of that should be introduction and the same for conclusion. So I write out intro, para 1, para 2, para 3 etc and conclusion, on a sheet of paper with big spaces underneath. Then I note how many words I have roughly per section. For each body section I write a note of what the main points I need to cover are, what evidence I'm using to support it, and why that evidence is relevant, finally why this point is relevant to the original question (the 'so what?' point). Also how the points follow on from each other. For the intro and conclusion I note what I need to cover. Remember the intro is a roadmap of your argument and the conclusion sums up, there shouldn't be anything in those parts that isn't supported in the body of the essay. For psychology essays I also have a separate page where I keep notes of what references I need to make sure I list, but she might not need that at this stage.
From there I can fill out the notes into sentences, and that pretty much gives you a first draft. Making the plan also helps with thinking about what needs to go in the essay and what doesn't.
Sometimes I do a second plan before I start writing if its not coming together, or swap paragraphs round to make things flow better. Sometimes I scribble points on post it notes and shuffle them about too. A plan is helpful if you have to go away and come back to the work as well.
Sorry this turned out massively long. Probably should have done an essay plan!! Hope it helps though :)