Talk to Gastroenterologist on Severe Pain Below Abdomen

Aoa. I wanted to know my father already had brain tumor operated 18 years back due to which his one side is paralyzed. But since two days he is having severe pain in abdomen but the pain circultes sometimes goes at the back but the intensity of pain is svere. This happened suddenly he was alright but after eating dinner he started feeling the pain. But since long he is having cough and mucous. I wanted to know the pain is due to some chest infection or is it urinary pain. After the medicines now he feels restlessness. Please help. And how to reduce pain although he has taken medicines from two doctores here. Not much diff in pain.