Assuming both sides were greedy and spiteful, that leaves the fact that one side wanted to care for her, and the other wanted her dead so he could continue on with his shackup. Looking at motives, it's clear MS had personal reasons for wanting her dead, the parents had none.
At the medical malpractice trial against doctors who treated Schiavo in 1992, Mary Schindler spoke with admiration about Schiavo's attentiveness to her disabled daughter.
"He's there every day," she said. "He is loving, caring. I don't know of any young boy that would be as attentive. ... He's just been unbelieveable. And I know without him there is no way I could have survived all this."
On her grave marker he has inscribed, "I kept my promise Terri".