User blog comment:Bato of the Heavy Iron Rock Hammer/Other Ten Wizard Saints/@comment-41.136.22.78-20150724164350/@comment-7418318-20150726144401

They were certainly alive enough to comment on Hades' death before Acnologia attacked.

If Zeref wanted them dead, he'd have just killed them together with Hades. Since there's no real reason to wait and kill them later, I strongly assume Zeref let them live.