Let me answer in your order. If you require unanimity, 1 quack with a made-as-instructed opinion, outweighs 100 qualified and credentialed experts. Lawsuits are never decided that way -- nor should they be. In determining facts, the trier of fact always weighs the relative strengths of the opinions of the various proffered experts.
The parents' two doctors weren't "ignored". They both agreed that Terri was in a PVS state, however, without any support in any medical literature anywhere, they opined that their respective 'experimental therapies' ("hyperbaric" in one instance and "vasodilation" in the other) might have a beneficial effect. Their inability to demonstrate, scientifically, the efficacy of their desired courses of action led to their opinions being given less weight than others (as they should have been), not "ignored".
You are wrong the 2 doctors of the Shindlers said she was NOT PVS. And the 2 Dr.s from MS were pro euthanasia. The court Dr was biased as well. So much for a fair diagnosis to base a death sentence on. This court was no different from the court in Alice in Wonderland.