One extra bit of advice that i remember helped a friend with this fight(i havent watched the video, so if its already covered then ignore me). As i remember that fight, one move he does involves jumping back and doing a 6 or 8 line attack in all directions around him. So when he jumps back, taking an extra step or two away would give you more room to avoid the upcoming move(and potentially time to down a potion or use a heal like 2nd wind). You can always use a gap closer after the attack finishes to get back on offense.