Somebody targeted him.
did he have all the IOU accounts in his pocket?
Just saying, there will be another statement in a week or so...
Could be a heart aneurism. A lot of people go this way which are reported as merely as “heart attacks”. The pressurization of the cabin could be contributory too. Good medical care, followed closely, might have prevented it.
However, the cause is merely speculation on my part. But the odds are better, IMHO, than his being taken out.