The body of Galen must be dead and the written must be gray, the health bar must have written dead, only the ghost must be full heath.  When i take the quest "Galaen's Fate" the ghost must only appear and start a dialogue.  The ghost of Galaen appear and the blood elf engage the fight with the ghost. So the fight between ghost of Galaen and blood elf it doesn't have to be.  the fix must be how the video https://www.wowhead.com/quest=9579/galaens-fate#videos:id=115448