It's hard for me to imagine the bravery it takes to sign up for this -- even if you're dying already, something like this is unlikely to result in a peaceful final days on earth (between being a science experiment, the media, optional major traumatic surgery, etc...). The folks undergoing this are incredibly admirable.
Maybe volunteering for this procedure makes the patient get prioritised for a human kidney transplant?
No, that would be unethical to dangle a carrot.
From what I’ve read, it is that these patients are too far along for much hope of anything. I’d certainly like to go out adding to the hope that future patients don’t have to suffer the same fate.