User blog comment:Warya123456/Is Aizen really dead?/@comment-2171236-20100801013418

Aizen couldn't have used Kyoka Suigetsu because Gin said he finally knew how to stop him from using Kyoka Suigetsu: By touching the sword before he activates it's hypnosis. I don't think that kubo would get rid of Aizen that easily. He will probably find some way to survive.