He is not very afraid of her, when he sees her the first time. The second time, she is in front of him and he isn't that nervous. I would run away if is see it in the corner. He keeps cool
Taking as a working hypothesis that this footage is true, I do not think that it is very frightening.
Why should one be more afraid of a ghost child then of a living one?
I search around on the internet but I cannot find anyone mentioning that they have actually tried to soothe a crying ghost child.
A human (humane) reaction to seeing a child cry is to seek to comfort her, to try and find what ails her. Given the chance, I would try the same for a ghost.