I was tempted to strike the relative clause containing yet another assertion of disputed fact as if it were undisputed. Hint: it starts with "who". But I'm increasingly impressed with the uselessness of educating you on the difference between fact and opinion, or between assertion and proof. So I'll answer your question as it was posed.
First, you appear to be misusing the word "voluntarily". She swallowed her own saliva, which is sufficient motility for her to be given liquids. Whether this is "reflex" or an act of will is not relevant; you seem to be using the adjective "voluntarily" in order to simultaneously recall her impaired mental state and also falsely suggest that she is incapable of receiving nourishment PO.
I just realized that this should be pointed out, because not all readers have worked as health-care professionals, as I have, and so they might not realize that your wording, which I've ignored as meaningless, is indeed meaningless.
Second, supposing she could not swallow at all, as you appear to be trying to imply falsely, there is still a benefit to the exercise: her grieving family members would be able to see that she truly could not swallow, which would help them release the false hope they had clung to for so long, and come to grips with her PVS.
Schiavo would be able to position himself in the middle ground--allowing nature to take its course, while allowing the parents to make their final, fruitless efforts to save their loved one. Terri gets her wish, the parents are permitted to make their best peace with the tragedy, Schiavo gets good PR, and he escapes the family's hatred as well as whatever repercussions might proceed from that. It's win-win-win, for him, Terri and Terri's parents. (Again, assuming that everything Schiavo said in the case were gospel truth.)
Baloney. She would drown.
"Second, supposing she could not swallow at all, as you appear to be trying to imply falsely,"
"Supposing"? "Appear"? "To be trying"? "To imply"? You got enough modifiers in there to accuse me of anything.
Where did I do that? I've stated as a fact numerous times on this thread that she could swallow. Just not voluntarily.
"and also falsely suggest that she is incapable of receiving nourishment PO."
She was incapable of receiving nourishment PO. Geez Louise.
"there is still a benefit to the exercise:"
Yeah, there's a benefit all right. All you Terri-bots could then say, "If the doctors said she couldn't swallow, then why did they test her again? And if they questioned her ability to swallow, then why didn't they question their other assertions? Terri needs more tests. And more tests. And more tests."
And the autopsy is suspect. Let's exhume the body! Oh wait, you can't do that, can you? But I bet you'd try if she wasn't cremated, wouldn't you?