It's a good question. We can only think in our earthly terms. We cannot imagine what God's plan is.
God's will will be done.
My prayers are with Terri and her family. I'm glad that a friar from our state, Brother O'Donnell is there to help Terri's family. He and other friars cared for their founder who suffered brain damage after a bacterial pneumonia infection. Brother Gaworski lived 12-1/2 years (in a persistive vegetative state) in the friar's care and died of natural causes. O'Donnell met Terri's brother last year at a DC Right to Life conference and has spent hundreds of hours with the family.