A mind seized by fear is thrown about without mercy, torn between impulses it did not choose, wasting away because it believes an alien power moves it from within. The father who describes his son is describing the terror of watching a beloved part of oneself convulse under a force that seems stronger than every attempt to help.
The helpers could not cast it out, for fear is not undone by fear or by effort that still believes the affliction is real. Only a strength that knows the torment is a figure in a dream can lift it, because it looks past the convulsion to the quiet Self that was never truly touched.
Son: the part of the mind that appears possessed by fear and helpless before it.
Father: the mind's tenderness toward its own suffering, love pleading for the release of what it cherishes.