What the hell? lol, I can't win the battle...
1. Esteban doesn't want to heal me anymore
2. Ennemies don't want to drop ANY weapons or the game is just so crappy that it is too hard to walk on a weapon and grab it, I can't even see anything of a weapon after killing like 5 buddies in the same spot... and my weapon get broken so I die sooooo easily
3. Everytime I try to use fire on the ennemies, de Bayle only start shooting stupid fire to the boss and I'm stuck with that, you can't undo the action until you get a sh**load of combo on your back...
What to do?
Stun attacks. Maelstrom as you know automatically puts you into the fire thing as does anytime you button press to avoid enemy fire. Since Esteban doesnt heal well in this one (since hes always fighting) your only choice is to mash LT+A or regular B on enemies. Don't forget that you can stun the boss with B to catch some air.
Certainly the most annoying fight in game. So just try working with B and LT+A while avoiding LT+B. When everything is stunned, try and start up the fire attack or try healing. Good luck healing though, Esteban would rather use fire.
Thanks, I'll try again this afternoon :P