I finally got this to drop for me today.
I have been camping both courtyards almost every day for the past 3 weeks.
Weekdays about 3-4 hours a day and 8-10 hours on weekends. I would estimate that I have killed the Sentry of Sathir 40-50 times.
95% of his drops are the helm. When he finally dropped the sword, he did not appear as holding a weapon.
Most of his pops were in the "right side" courtyard, but he did pop in both sides for me. A few times I even had two up at once. And funny enough, when he finally dropped the sword for me, there were two up and both dropped the sword.
Good luck to you if you decide to try to get this.