I take it you explained why you were cancelling? As a matter of interest, how much notice did you give her?
On a technical point, I'm not sure it qualifies as a review as you cancelled, rather than her; would be a post on the South East regional discussion board.
I am sure a lot of punters cancel on her claiming a family emergency or similar and very few are genuine, so she is probably fed up with hearing that.
However, yes, it is unprofessional to take that attitude if you gave her quite a lot of notice, given it might be true in cases such as yours.
I hope your friend makes a good recovery.