Advice needed

My father has been diagnosed with a 3+3 Gleason (this parameter was said to be good in the beginning, but I fear this test went wrong given what comes next) prostate cancer just a year ago. He was 52, he didn't have particular symptomps and got to know he had prostate cancer because of another problem (inguinal hernia) who was completely eliminated thanks to surgery last summer. When he discovered he had cancer the tumor was already metastatic and the PSA level was in the 30-35 range. He started taking hormone therapy (decapeptil) every month. He immediately started having problems in his legs, feeling light pain and having small difficulties to walk. He couldn't start chemo because of his liver: the surgery required a lot of pain killers and his values were too high to start chemo. The situation was quite stable until December when things started to worsen, his PSA (which was 7 at his lowest point in September) was above 10 and he started to have periods in which he could hardly walk without a crutch (first "crisis" was around Christmas). He had his second PET which showed cancer was spreading. Just after the holidays he started chemoteraphy using docetaxal and started taking pain-killers daily and not only when needed (mainly opioids, to which he is quite resistant). His conditions started to worsen again in February and PSA continued to rise, from 10 to 20 to 30 and so on. Another PET was done in middle April and, together with a PSA of 50 (!), showed chemo completely failed. He was asked if he preferred to be treated with another kind of chemo or with Abiraterone or Enzalutamide. He chose to use Enzalutamide and is now being treated with that. But his conditions are now quite worrying, he can't walk without using two crutches and pain killers don't give much relief. Due to his insistence he is now scheduled to have radioteraphy on May 8, hoping this can improve his conditions a bit. Seeing how things went till now I strongly doubt Enzalutamide will do much. I know there are other teraphies like Radio 223 or ipilimumab but these weren't among the options given. I wanted to tell this story also to know if others in similar conditions had benefits from different cures. Personally, I find the situation quite worrisome. The quality of his life decreased terribly in this last week. He is now unable to walk outside our house... doctors are always optimist but I am not of the same advice.

It is very unusual that Gleason 6 prostate cancer with a PSA under 200 would cause such severe symptoms..How old is your Father and where is he being treated ? Maybe his doctors who are focused on treating his cancer are missing something else that is destroying his quality of life......Has he had a Bone Scan, different than a PET/CT? This will pin-point bone mets and may be useful in explaining his loss of mobility....