Fans are asked to pledge $30 � all of which will go to the charity and they'll receive a Williams t-shirt in return. The band say: "People assume drugs and alcohol are the cause when the news reports that a rock star has died. Dave actually died of the heart disease known as cardiomyopathy � disease of the heart muscle and Dave didn't know he had it. It often goes undiagnosed and affects people of all races and ages.