NFL prospect found Dead

This is crazy it seems this is becoming more and more prevalent these days. Young athletes seemingly in "perfect" health die for no apparent reason. So what are these team doctors are checking or not checking for when they give these kids physicals? I don't get it at all, I mean my little brother was told he couldn't play high school football because he had a heart murmur and that was the end of that. That's why I don't understand how this happens at these schools with million dollar coaching staffs and equipment. Heath Benedict was only 24 rated the 9th best guard at 6'6 335 by sporting news draft guide '08, he was projected to be 4th round draft choice.