Bumping this to the top. This is something I was wondering about as well, so any info would be appreciated! My guess is that it will all be hushed up. From what I've read about a similar missionary death in the past (sorry, I can't remember the link), not even the missionary's family may know all of the details. Sad, really.
This elder was a family members companion. From what I understand he had a heart condition before the mission and was cleared to go and was told he was going to have to go home and have surgery. The mission was working to get him sent home and he died of cardiac arrest. That is what we were told. My thoughts to his family, he hadn't been out too long.