There haven't been any case of a dead user of this forum I've come across, but on the other forum, there are several users who are late and one can easily tell by visiting their forum profile, there is a special note which says "in memorial" that is added just under their forum scores. I don't know about other users but I personally find this feature very useful, but then, before a user that is late gets such title in his or her profile, there have to be a confirmation of that user's death from multiple reliable and well trusted users on the forum.
It is not a must do, like it's not really an obligation for admin here but then, he can try to emulate same thing so that other users can easily spot profiles of users that are late.
And concerning whether or if the user was owning another forum user before death struck, it's simply what it is, there is nothing the user who was owed can do except forget about the money.
Except the family of the deceased knows about the deceased activities on this forum and decides to settle the dept/loan, this has nothing to do with admin or the management of this forum.