PC SOLUTION ONLY. Guys, I've been trying for months to fix this quest and I finally did. So first of all I realized the quest was completely glitched because CuSith was dead. I obtained Auriel's bow, but Kindred Judgement never started. I could speak with Serana about the arrows but no dialogue would come out of it.
So what I figured out to do was bring him back. Open the console command, and type helpCuSith. You will then see a number that says 0501AA78 Next, Type player.placeatme 0501AA78 1
That will bring back CuSith. The reason the quest wouldn't start was only because he was dead, or the other dog Garmr, (so if you lost Garmr do the same with him, his will be a diff number)
Finally now when you set the stage it WILL ACTUALLY WORK, as before it never did. So I just typed in SetStage DLC1VQ08 10
And 10 is where the conversation with Serana begins and the quest starts. I'm so happy to have finally found a solution for this. I hope this helps anyone else who was struggling.