A clogging artery can cause that, too. Trust me, I know this first hand. But I do not rule out foul play. Things always seem to work out in favor of the Marxists, otherwise I would not be suspicious. If he was out hunting he could’ve been bit by something deadly and had a slow reaction to it.
I know. He was no spring chicken. And I had a brother die of a clogged artery before he was 40.
But considering the PTB now, suspicion is the first thing that comes to mind. Like you, I do not rule out foul play.