Jaren Ward had the light RIPPED from his body because of Thorn. He couldn’t be resurrected. Jaren Ward’s ghost then returned to Shin Malphur and GIFTED HIM THE LIGHT. This is the only time this has happened in the lore. But it is possible. Now comes the second aspect of my point. Rezyl Azzir’s ghost left him. But a new ghost could find Dredgen Yor and claim him. There isn’t exactly a canon reason as to what makes you worthy of the light. Yor was devoted to the Sword Logic. He was always brave, so much so that he took on Jaren Ward. He sacrificed his life to prove a point to Shin Malphur and other guardians about having to walk the line between light and darkness. Devotion, bravery, sacrifice and death. These are the four things that are stated to make one worthy of the Light. Who’s to say that a ghost that follows Savathûn can’t find Dredgen Yor and bring him back? Who’s to say that Bael himself won’t find a way to resurrect him?