User blog comment:Toshiroichigo/Kensei and Rose's Deaths- Were they Necessary?/@comment-5398287-20140430220623/@comment-24113610-20140430225505

What Gremmy did to kill them was actually never revealed though. But if he did imagine them dead then it can be assumed he stopped focusing on them at some point during his fight with so they're no longer dead.

Remember, Kenpachi was able to move Yachiru because he made Gremmy forget all about her cookie bones so it also be assumed her arm is still broken but it's not made of cookies anymore.