Diagnosis of metastasized cancer

A 60-year-old male is in the infirmary for increased abdominal pain related to the diagnosis of Cancer that has metastasized. He has been in prison since he was 22 yrs. old due to the multiple rape and beating of a 16 yr old. He held her for several days before he strangled her then dismembered her body. He is requesting more pain medication though his vital signs have not changed, and his demeanor is calm. He has soiled his linen with both feces and urine which he does quite frequently. The charge nurse’s routine is to withhold the medication until he appears to be in pain. The night nurse feels it should be given knowing pain is exacerbated at night. What should the nurse do?