He did not drop Minotaur Helm.

Use either the large club or great club to continuously smash him to the floor

I've found the best way to deal with this guy is the "big weapon + big shield" combo. Nothing he has can really get through a high-stability shield, and his weapon-swapping can be greatly punished with a greataxe, greathammer, or greatsword. Backstabs with those weapons, while shield-strafing or while he's swapping weapons, will make swift work of him.

He pulled out a Ricard's Rapier on me and stunlocked me to death. Or some kind of rapid thrusting attack. Looked like a rapier though.

I beat Akinator the web genie with this guy.