@mushroomfemboy @Sp @sandy those responsibilities/privileges of decision making are no different than they are with a live vegetable in a coma.
in all situations, society expects the deceased/etc subject to have written a will or other legally notarized document stating the intent to consent or refute to specific treatments posthumously. in the event that circumstances do not allow for that to be followed, or a clear will of the actual owner cannot be acquired, the family (or other legal entity; it isn't always a relative or spouse or child), the any decisions that need to be made which are not accounted for become the responsiility falls to whoever that "next of kin" or legal representative is.
the body itself has the right to not be desecrated and to be interred or otherwise dealt with in a respectful fashion (determined by culture and religion mainly). nobody else gets rights to the body unless consent is provided prior to death, or the legally responsible party gives consent posthumously. that party doesn't have "rights" over the corpse, only the responsibility to represent the best interests and wishes of the deceased individual. and that isn't even proper representative authority; if the goverment feels like it wants to refuse and do as it pleases with the corpse (usually in relation to criminal autopsies) the govt does as it fucking pleases.
people don't really care though. they care that burial services and coffins are maliciously overpriced, and they care about putting up a front and hosting a big cry-fest wake to score pity points and compete for whatever elements of the deceased's estates are unaccounted for or unclearly determined by the will (if there even is one).
you have no privileges, just responsibility - and an expensive one, if you don't just tell the coroner to ship the corpse off to the nearest crematorium and mail back a bag of mixed ashes.