Hello cureit ..........
You are dealing with a lot, and I know how confusing some of the numbers and explanations can be at times. It sounds as though your Dad's issues with Alzheimers are very manageable at this point, so that should help ease your burden.
My Mother has dementia (similar to Alzheimers), and she is much older than your Dad and is at a different stage of dependance ... but I have an appreciation of that, as well as, having advanced Prostate Cancer myself.
Since my age is very close to your Dad's ... at 70-years old, maybe I can give you some degree of hope for your Dad in dealing with the Prostate Cancer. While I don't have some of your Dad's other health issues, I have additional ones with COPD and severe Kidney issues.
I just had a CT scan and a Bone scan yesterday and will be reviewing my next directional change with my Onco next week. But, hopefully to ease your mind a little, I am in my tenth year of dealing with PSA readings - and even though I have gone thru all three of the meds that TC-LasVegas mentioned below ... there still are options.
It's confusing ....... it's scary ....... but your Dad should be proud that he has you in his corner.
By the way, my PC did spread to the lymph nodes at least two years ago and slightly into the bones at that time also. Since my PC seems to be very resistant to the recent Xtandi oral chemo, a bone scan was done to determine "what's next"!
My best wishes to you and your Dad.
Rob