Why jump though so many hoops to kill yourself? You could set out to sail on a beautiful day, take a lethal overdose and die peacefully doing what you love best. Your relatives are not wondering for days what happened to you, and are not presented with a bloated corpse.
I agree, the circumstances are VERY strange, to say the least.
But remember that we dont have, and will never have, all the information. Did the poor guy just find out from his MD that he had inoperable cancer? Had he been started on a new med(s) that changed his outlook?
Did he know something that was not to come out?
That being said, the method of death was odd.......I am sure that it could be done alone, but why????