Families and friends often just want to know.
Return of remains is one way to know, but not the only way.
People who love a person whose passion is space travel would probably understand about burial in space, and might even consider it to be poetic. Ritual and expectations established beforehand, including an inquest, give the living a way to act during a time of loss and stress.
Religious requirements need to be considered as well. The bodies of Muslims, for example, are supposed to be buried, as in "a hole in the ground", within 24 hours. Pretty impossible. Muslim astronauts need to talk about that.