I don't think there's any question that he had made his mind up about Terri's PVS state before filing that legal action. What he thought it was, I don't know, but I'm sure Felos convinced him that he could win on the PVS issue.
At that point, the die was cast. Michael and Felos weren't going to allow any more tests that might contradict their position.
Michael wasn't looking out for Terri's best interests up to the bitter end. That ended sometime before he filed the legal action.
IMHO, Michael should have been deemed to have divorced his wife when he destroyed her wedding rings. He cannot be presumed to have had her interests at heart any time after he admitted in 1993 to having done so.
The legal posture and conclusion is the opposite. That he was looking out for her best interests. Given her condition, and the court-determined patient's wish to be dead, her best interests were to obtain a natural death by starvation. It just happens that Michael's testimony and sense of "best interests" and the court's finding of "best interests" are congruent in this case, they needn't always be.