My Brother Is A 50 Year Old Health Nut,but He

My brother is a 50 year old health nut,but he became very ill about a week ago.Some of his symptoms was he had severe abdominal pain,fatigue,and shortness of breath.He went to several doctors and they ran all the necessary tests and everything came back negative.One doctor did say he had an enlarged heart and was given a prescription but he has not made any progress.Please help!(Worried brother)