That's actually a good question. Without disclosing too much of her psych history, she seems to be really impulsive and might even be prone to addiction. I suppose she could get an exercise disorder... this makes it even more complicated than I thought.
I'd caution that suspecting (out loud) that she might develop an exercise disorder would be one of those insulting or belittling things you were worried about (either because it seems like a cheap shot based on the anorexia diagnosis, or because this might be one approach to actually getting out from under the anorexia by exerting control over her body).
Likely a better approach to this concern would be to silently watch for those behaviours developing and worry about it if and when it actually does happen. (Note that refusing to help her with training and...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Duration set to six days to encourage Monday as first day.