Yeah, with your edit/further information, I don't think her personality/behavior is incompatible with ISFJ.
The lack of Fe/demonstrated care/concern/giving towards others is probably because she's in a place where she feels the need to care for and protect herself, and therefore she's willfully pushing others to the back burner. And part of this is probably subconscious, too, and I doubt she's even aware of much of herself. Especially when you mention her pattern of unhealthy romantic relationships....that also demonstrates her lack of esteem. Also she probably doesn't trust people easily, which would make it that much easier for her to push back and be almost anti-Fe. Hopefully at some point she'll be able to work herself into a healthier place, and find a better balance.
I don't think this is inconsistent with Fe, as speaking from my own behavior, I have done similarly in the past. Turned 'off' the Fe/feeling, such that I almost came to scorn it. It was purely self-protective, because I had been so sensitive growing up.
(also, enneagram-wise, she might be sp - self-protective - which again would lessen her demonstrated Fe traits)
And, I think this provides a good example of why one has to be careful with mbti, and not weigh it overly heavily in terms of a persons' psychology and behavior...I mean, there's so much more to psychology.