He has all the rights (The right not to be imprisoned nor abused, the right to a meaningful life while he waits for Tuvok and Neelix to be saved or given up on, etc), except the right to deny Tuvok and Neelix from being saved if possible. Once that possibility is given up, then he also inherits the right to keep the body.
So what about Lyndsay Ballard in "Ashes to Ashes"? She was just as dead as Neelix and Tuvok. However, Janeway let the new lifeform in her body run off with Lyndsay's biologically alive body and memories. How did the new lifeform there have more rights as an individual than Tuvix? Or was it because the ship was threatened, the individual was sacrificed for the good of the group?