I can't say that I major problems with morphine. I also took 30 mg for breakthrough pain (in addition to the fentanyl patches). I don't remember ever even getting a buzz off the stuff. It did cause constipation and that made me sick but it was better than the pain and besides I didn't had a PEG so pain management was pretty vital. Some people here have had really severe reactions to the morphine. It is very fast acting and generally handy for that purpose. Maybe my memory has improved now that I don't take it anymore. It is a narcotic after all - it's supposed to have some side effects.
I would be more concerned about that fact it's not relieving his pain - that's a serious issue. Maybe oxycontin would work better - I would run that by the doctor. Effective pain management is a basic patient right.