Laurence legs

i was fighting laurence for the 3rd time (i think) and at like 30% hp his legs just disappeared, and i thought; "oh, now that he is disabled, the fight might be easier" then he just killed me with some strong/random attacks and i died, so now i have some questions:
1 - Are his legs guaranteed to come off or depends on the fight?
2 - After losing his legs, the fight becomes easier or harder?