My 94-year-old mother's health is declining and she talks frequently about death. Is she preparing to die by talking this way?

My mother has fallen so many times and hit her head. She also fell and had a brain bleed because she was on a blood thinner. She had a stroke and is now wheelchair bound. My Sister and I know her memory is getting really bad. When she has been in emergency rooms, they said she has dementia. Two months ago, she walked out the back door of her house without a walker, fell and had to crawl back in the house. My Sister has the house locked to the point that she can't get out because she doesn’t have the strength. She told me yesterday that she stayed in the bed all night and day, but my sister said that was not the case, plus I talked to her on the phone that day. She keeps asking me why she is still living. She asked me today when she will die. She also asked me if her Dr. could prescribe something to help her die. Is she preparing die by talking this way? I am really hurting from this emotionally. Any advice from anyone would be greatly appreciated. Thank you.