As far as I am aware, some faiths use the term 'passed' because it means they have passed over to the other side, which is what they believe. I don't like it myself, but that is neither here nor there.
But when you are writing an obituary, it seems to me that the term 'died' can be used, but not constantly through the entire article. For instance 'With her passing, we see the end of an era' is fine. Especially if everyone reading it knows exactly what it means.
However, that is beside the point really. This woman has used the death of a much-loved national treasure for egotistical self-promotion, which is pretty low.