What Causes Abdominal Pain When Treating Metastatic Prostate Cancer And Hepatitis-C?

My husband ie 63, he has matastic prostate cancer and hepatitis c. 3:30 this morning he woke up with abdominal pain and lots of gas he couldn t move. Gave him an anti gas and he was able to go. This morning he woke up still hurting and nausea. Gave him a promethazine12.5 mg and a mild laxative. He was able to pass some but he passed gas and some bloody mucus came out ,then when he had the bowel movement there was blood as well.