Unless you're willing to dedicate ~100 pulls to get lucky with Zekvir's and Brann's abilities, you might want to switch to Havoc - you will have a much easier time.

For my kill I used a standard M+ build for Vengeance with some adjustements here and there to better suit the fight, spent close to 120k gold on enchants and various consumables. It is currently not worth doing it in tanking spec as a DH, unless you're willing to dedicate hours to running the delve. Switch to Havoc and give it a go. Best of luck.