kidney stent for chemotherapy

My father has bladder cancer that has spread to his kidney, liver and his bones. He's getting just radiation but the Doctor wants to give him chemo to extend his life. His kidney has a blockage even though he's urinating a lot, but with a good amount of blood. They want to put in a kidney Stent to be able to give him chemo. My question is  should he have this surgery and how much pain is involved if he decides to have the surgery and for how long will the pain last. Do you think he have a good chance of going in remission if he have the surgery and the chemo, My dad dosen't handle pain well and is very apprehensive about doing anything else since the cancer has already spreaded to these areas. We don't want him to give up, but we also don't want him in unnecessary pain and suffering. What would you recommend?