“Was she aware the McCain was dying of a fatal disease that was destroying his brain at that time?”
This is not true for every one who dies of Brain Cancer. My dad died of the same Brain Cancer as McCain (i.e GBM) eight years ago and he was still himself until he was unable to talk a few days before he died. In fact, one of the last tings he ever told me is to not let his passing negatively affect my life. He was a good father until the vey end whereas McCain was a bitter old, Judas scumbag until the very end.
I think it depends upon where the tumor is located in the brain.