Just to learn how someone died is not a right of the diving community. Unless a family wants to conduct an investigation or the death is suspicious in some way, there is no mandatory reason for autopsy and even if there was one, divers should not presume that they have some right to that information. They don't.
Too often, members of the community think they have some special right to information about accidents on the theory they will learn from it. Such a right does not exist and even if it did, the privacy interests of the family prevail over it.
As an aside, this board is full of incredible speculative analysis of accidents based on none or very little information - often hearsay. It is hard to believe the dive community, on a board like this, can benefit from such information.