Let us posit, perhaps, he wanted her to live; but when he realized her life was not going to improve beyond being in diapers, immovable, and incapable of responding beyond the barest of physical responses....he slowly made a much more realistic realization.
He may have fought against the realization of how bad off she truly was, insisting to himself that she would recover. Once he realized that was an impossible dream, he remembered her statements. I don't find it all that hard to believe.
I want to live, but if my life hung on the same threads as Terri's...I would want my wife to choose for me as Michael has for Terri.
If we are dealing with clear and convincing evidence this is a flip flop pure and simple.