I'm so sorry to hear about your husband. I agree that you should get him to go to another oncologist. You should also look into maybe going to a big treatment hospital. There are many and maybe one in your area.
Watching a loved one is so much pain is horrible. I watched my dad get sicker each day after he was dx with prostrate cancer. Is your husband still on chemo? The big treatment hospitals might have some luck with helping the pain. Also, if he isn't on chemo, have you tried hospice? I have been told that they are very good at pain management. Being in pain all the time is very dibilitating. I am sending prayers to you and your husband that you find what you need.
Lisa