I think the problem is that someone like Grace has only had a very limited experience with food and the perception of health: in her mind, there is only dieting or eating with abandon.
She probably really needs calories at this moment in time, so she shouldn’t be dieting or worrying about calorie intake. However, she absolutely should be paying very close attention to nutrients, ensuring she gets plenty of protein, fibre, vits & minerals, stays hydrated etc.
She shouldn’t be worrying about weight in my opinion but I really don’t think eating takeaways with abandon is a good idea. Plenty of really good nutritious food and a lot of water would be the sensible goal, to do everything she can to aid her body in recovery. A side effect would be slow and steady weight loss (without losing more muscle).