I don't think a dermatologist is qualified to make the decision if she should see another doctor or not.
She should see a rheumatologist in my opinion.
Her dry eyes indicate that she could have sjoegrens, another reason to see a rheumy.
Please suggest to her to make an appointment now, because sometimes it takes months, before you can get a first appointment with a rheumy, just because they are so busy.
That is what I would do, better safe than sorry.
I may have been dealt a bad hand, but at least I'm still playing with a full deck. ( most of the time anyway).