sifting thru the causes one statement suggested Respiratory Failure another Heart attack- I suspect he had a dilated cardiomyopathy with Congestive heart failure and simply died of pulmonary and cardiac failure- steroids could be a culprit although idiopathic could be as likely if not more likely-
cousin of similar dimensions had the same problem although he was 6'3 and 300lbs developed CHF- suspected viral etiology died at 44...