Max hit on a group geared (TBM/TDS) tank with only 12k AC and 150k HP buffed was about 17k. Most annoying are the spells which are easily cured by radiant cure or for a rogue with Purge Poison AA.
If you want to have him solo easy then after clearing the basement/lower floor, drop the task and if you get it again then all trash is cleared. This seems a bug at this time and it worked (for us after about 1 day between drop and re-get). If not then you have to deal with his two buddies and the adds around or a good puller ;)