I think that they just mean that he did not die of injury. There are still further tests to be run that might lead to a more precise cause being established.
I think it is likely that he was aiming to get to the Marina, and then pause and refresh, and then decide whether to continue, get a water taxi or return the way he came and get a bus.
I think it's very likely that he missed the turn to the lower col route that is the shortest and less risky path that would take him to the south entrance. Given the last sighting of him on the marina's CCTV and the length of time he was walking on harder trail, he may well have have been able to completed the lower route.
But a blogger who was linked to an earlier thread, and who was attempting the same walk, took a wrong turn, found himself on the higher col (which set his spidey senses tingling because no footprints - people really don't go that way). It sounds like it's an easy mistake to make.
So perhaps he only realised higher up that the marina was nor where he expected it to be. It looks much steeper (and there is no path) to turn hard right to the southern entrance. So carrying on a bit then dropping down to the north entrance would have seemed the more sensible choice - by that point, and exhausted, it probably was. And he nearly made it.
RIP