When Abigail died I sat down with Annabelle and told her what happened, which seemed kinda silly when I was doing it, but like someone else said earlier, I think she got it. I also had Abigail cremated and let Annabelle sniff her ashes and explore them. She calmed down after that and sometimes goes over to the jar where we keep Abby's ashes. We tried to give her lots of extra attention and got her a "pet" kitten when her leukemia incubation period was over.