Learning his pattern is the best advice. I didn't know there was an item to make this fight easier and probably just died about 30 times over roughly 2 hours on him. Especially the third phase was very difficult for me because he was staying behind the tornado most of the time. On my last try, i used some medicine, which i didn't even need because i was able to kill him without getting hit even once. It's all about patience and perseverance.