22 months ago my father was diagnosed with prostate cancer. He had brachy therapy and hormonal treatment. In January his PSA count was 6.4, now it is 130. the cancer has spread to his bones and he is unable to walk. He sleeps most of the day, and eats VERY little. He has also deteriorated mentally to a stage where he is unable to construct sentences or remember what happened five minutes ago. He still remembers closely related people but sometimes forgets their names.
I was wondering if anyone could shed some light on why his cognitive state is so badly deteriorated and what we can expect next as he is getting worse every second day.