I Was In The Hospital For 2 Days And My

I was in the hospital for 2 days and my husband stayed with me the whole time. The day after we got home he developed diarrhea and stomach cramps. It has been a week and anytime he eats anything he gets mid abdominal pain and has diarrhea until there is nothing left. He is tired of the pain and diarrhea but I don't know what to tell him about the cause and treatment.