I am sorry that your Father's prostate cancer levels are increasing and that it has spread to the bones.
I can only "share" my Father's experience with you. Chemo was never offered to my Father - until his final stages. The oncologist told him that it had a 10% chance of "extending" his life but 0% chance of a cure. I was under the impression that Chemo would not cure prostate cancer.
My Father was diagnosed w/ prostate cancer in 1995 at the age of 73. His original levels were 78.7 - they assumed he had this illness for many years before the diagnosis. He also experienced many other health conditions and they said - just do hormonal therapy - something else will get you first. He did several different kinds of horomal therapy (Eulexin, Prozcar, Casodex and finally Lupron 4 month injections) - these all kept his levels manageable for about 8 1/2 years.
Then the cancer became hormone refractory and spread to his bone and lymph nodes. They tried ketokonazole (spelling?) - which was too much for him to handle - but it does have a 25% chance of decreasing levels. His body at that point could not tolerate it. For the bone cancer pain they had him on Zometa - which did work wonders.
You mentioned nowhere in your post that your Father ever tried hormonal therapy. If he has not - that is a GREAT option - cause typically prostate cancer will respond for a certain period of time to hormonal therapy - until the cancer gets smart enough - but it can buy lots of time. I would mention that to your Father and his Oncologist.
When my Father's cancer turned "terminal" - his PSA levels were 2200 - they stopped doing levels in January - when they were 3750. He died in June. But overall he had great success from the hormonal therapy. And although I wish there would have been more they could have done - he did not suffer - like I would have expected a cancer patient to do so. The medications (zometa) and calcium supplements really decreased the bone pain. He died 23 days before his 10 year anniversary of being diagnosed with the disease.
Had he of had a radical prosectomy and radition followed by horomonal therapy - he would have more likely lived longer.
I hope this helps. I can only share my experience. Good luck and God speed.
Janet