Just a note on this. The United Supreme Court only looks at a VERY narrow argument. They never look at a whole case. It is up to the attorneys to find the best argument for their client. They did not do so for Terri. 'Clear and convincing' evidence was not brought to their attention.
The problem is that if evidence and witnesses that favored Michael were all viewed in the most favorable possible light, and those opposed were viewed in the worst possible light, there would be "clear and compelling" evidence. The fact that no reasonable judge would view Michael's evidence as favorably as Greer does, nor discount opposing evidence as thoroughly as Greer does, is not basis for appellate review. The most such a review could accomplish would be to have the case bumped back to Judge Greer in case he might have failed to consider something.