Physical signs of impending death?

My grandmother is in her early 80's and was put in the hospital yesterday. She has suffered from diabetes and congestive heart failure for years. She had a bout with breast cancer a couple of years ago resulting in a masectomy, she also had cancer in the bottom of her right foot which they removed but she has had numerous infections in it since which is why she was put on heavy antibiotics last week.
My grandfather passed away from lung cancer back in 2000 and every since then my grandma has deteriorated. Yesterday morning she was disoriented, won't answer questions when asked or says something off the wall, she cannot control her bladder or bowels and can't walk. This all happened over the weekend. She has been weak but not in the incapacitated state she is in now. She had to have an IV placed in her neck this morning b/c the veins in her hands and arms have shrunk.
Are these signs of impending death? Are there any other than the coldness starting in the limbs that I should look out for? What have you seen in your patients? I don't want to let my grandma go, but I know that she is ready to join my grandpa.
I guess I am trying to prepare myself.
Thanks for your help.