Bose, you ask the same questions over and over again. It is extremely irritating and I am beginning to wonder whether you are taking the ssip.
Your dad has advanced prostate cancer and according to you, has had spinal cord compression in the past. SCC is not the same as having spinal mets. SCC cannot be cured but radiotherapy can reduce the pain temporarily and surgery can stabilise the spine if someone becomes paralysed or similar.
Chemo cannot cure your dad's SCC or his spinal Mets and is not known for reducing pain.
Your dad's cancer seems very advanced and it may be that nothing really works for very long in his case. But you should ask his doctors rather than keep asking the same questions repeatedly on here.