Hi ! My Dad Has Metastatic Prostate Cancer And He

Hi ! My dad has metastatic prostate cancer and he is taking xtandy from february this year but now his psa start rising . His MRI showed the cancer had spread to multiple places on the bones. He will need to start chemotherapy. I know that Docetaxel is the first choice. Do you have any suggestion about what supplements to take( if yes what?) and I read that adding Emcyt to the regular Docetaxel is a better choice...is that true? What other suggestions do you have?
I really appreciate any answers and advises! Thank you! Luca