Earlier quoted context omitted.
I don't find it compelling because I don't buy the premise, that a person whose brain has been separated from his body is anywhere at all. A simulation of life isn't life, and that's all this is. You have, on the one hand, a corpse relieved of its brain being used as a puppet, and on the other, a brain kept firing in a vat. It's popular to think of "ourselves" as a sort of "ghost in a machine," and we particularly as…
Is someone with a cochlear implant dead? How about someone using a BCI to move a mouse? Or a locked-in patient? Is there a minimum number of organic connections we need to be alive? How would you convince this person that their 'I' has died? I think these questions are exactly along the lines of the question this story begs.
"Convincing a person that their 'I' has died" is a category error, like a married bachelor. Corpses can't know they're dead, and anything simulating life for the corpse isn't a person to convince.
There might be some other entity deserving of rights that does exist. I'm not about to argue that only persons deserve rights. I don't think a horse is a person, but I do think it has a right not to be abused. There's a meaningful discussion to be had about what rights the corpse and simulation ought to have in this circumstance.
But "convincing a person their 'I' has died" is self-contradictory. Being able to put the words together in a syntactically coherent sentence doesn't make the idea possible.