agree with everything said hereLooking at the logs posted, the tank is correct, he seems to be dying from lack of heals, nothing else.
From the videos, he looks like he is strafing, you can tell the way the boss occasionally moves to the side, rather than in a straight line, and AI forces the boss to try and get in front of the tank (which when strafing is actually towards the middle of the room) remember, it's hard to tell because front of the tank is the whole 180% in front, like bosses it's either front or back, nothing else. Apart from that, he seems to be doing ok tbh