Hi Bose, this treatment is likely to produce a temporary remission, but with luck, that could last for years (as I described in my previous reply to you, based on the results of clinical trials). Every patient is different and so it is impossible to make a prediction for your father of how long he will respond. Also, PSA is not the only important measure. The other factors are how he is feeling (symptoms) and the results of the scans he will after the end of the chemo.
Good luck with everything!