Seems a bit presumptuous and negative. I posit that it's more complicated than just. Yes or no, perhaps the answer is both.
BPD, which is what we speculate she has, has a symptom of suicidal thoughts.
Borderline personality disorder (BPD) is a serious mental illness characterized by pervasive instability in moods, interpersonal relationships, self-image, and behavior.
www.nimh.nih.gov
But there is something else to note.
I theorize that it isn't her lying about feeling suicidal but rather she could've used the fact she felt that way to avoid abandonment. Abandonment that more likely than not was in her head.
How right or wrong such behavior is it subjective.
BUT I concede that it is toxic. Not in the Twitter way (which is probably what I was thinking when I read your first comment). But rather in the, that's a toxic-relationship, kind of way.