When can a person be called a PhD ABD?
Some people think it's ok to call yourself PhD ABD when in the Canadian or US system, you pass the qualifying exams and coursework, but haven't yet, or fail to ever, deliver the thesis.

But simply do not call yourself PhD ABD.

It's not attractive to advertise failure.

You're either a PhD candidate, or you're a PhD, or there's nothing to say on the subject (bar a line on the CV filling in the black hole on your timeline with discreet mention of an aborted doctorate). PhD ABD is a ludicrous pseudo-title.

A PhD that's All But Dissertation is like an espresso that is All But Coffee. It's hot water with a bit of sugar, thus defeating the entire purpose of the exercise.