Hello Rachel,
My husband Tony also has advanced Pca with multiple bone mets. Early this year he had a course of chemo (Docetaxel) which was aimed at prolonging the the time for which the cancer would respond to the hormone injections. This didn't seem to have much effect, as his PSA soon started to rocket back up. He was put on Enzalutamide, which seems to be becoming the standard next step in the treatment path.
So far, now in his second month of Enza, he's responding well, and feeling and looking well too. If it works (and some men respond better than others) we understand that this may buy him a better quality of life for perhaps 8 - 12 months. It's a way of postponing the more intrusive and unpleasant treatments. We are prepared for it to be less than this time, as Tony's cancer is very aggressive. We think the next step, when this fails, will be either Radium 223 or further chemo with Cabazitaxel (or possibly both in succession). Cabazitaxel is often given if Docetaxel is suspected not to have worked.
It really is quite difficult for anyone to say how much a particular treatment has helped, or what would have happened without it, so your Dad's lack of information on this is understandable. I do feel for you and your parents. These consultations are so stressful, especially if you are receiving news about how much longer you may have to live, and how and when you are likely to die. Even with a list of questions in your hand, it's easy to be a bit overwhelmed, especially if the oncologist says something unexpected.
Does your Dad have access to a cancer nurse? Even if he doesn't see one regularly, he probably has a phone number for one. One idea would be for your Dad to plan a phone consultation, or even a face-to-face chat, with a nurse, ideally a few days after an oncologist consultation, to discuss what they've been told and ask any further questions. Perhaps they might consider this in fhe New Year, to help get their heads around the likely options and treatments ahead.
I'm sure your parents appreciate your support and concern, but I'm also sure (speaking as a parent of adult children) that they will want you to live your life to the full and not weigh yourself down with worry on their behalf. I hope your Dad is well enough to enjoy the Christmas season and enjoy each day as it comes.
Marje