Reread that proposal; I think you may have missed something. If Terri's condition were indeed as dire as Michael claims, that proposal would result in her dying a lot sooner than Michael's current course of action. I wasn't aware of anything resembling that specific proposal (including the prohibition of tube feeding) having been offered to Michael, but if there had been I'd be curious what his specific objections would have been.
his specific objections
That Terri would not want to live under such circumstances, and nothing will prevent him from carrying out her {his} wishes!