Recorded little video, can't upload big file right now, so its 720p and about 2/3 of the fight, I died initially 2x, it was only attempt at this (rusty). It shows final of the fight, last ~1/3 of hp, which takes longest. Getting him to 30-40% takes really just about 1 minute, because of how effective CB is at full hp.
Hope this gives you idea how you are supposed to move. It is crucial to not die at that final stage when he is almost dead. You can keep trying this forever, amount of spawned skeletons doesn't matter.
I removed all charms that are after kabraxis, extra signets. Only thing this character is better vs when I wrote guide is few trophies on earlier charms (like 5% jday, +1skill ureh, some life from azmo etc).
But you can do it deathless if you are careful and practise that fight.