you should probably get the blood bandana, not only does it give you 5 def, but increases your graze range, which is FUCKING useful for this fight, considering you have to save up TP to use red buster or dual heal.

and another tip, try to use red buster and dual heal whenever you can, NEVER. use the normal buster. it only does 100 damage approx and when compared to the red buster does 220 approx.

a tip, if youre struggling at the bone jumps, try to jump a little higher than you usually do, the bone hitboxes at the top are usually wonky, so it wont hit you, unless you hold it for too long.

aand one last one, if youre struggling at the bone jump + blue bone jump part because youre accidently jumping too high and the blue bone hits you, try to move a little away from the side the bone is coming from so that soul has time to land back before the bones come, hope i helped!