It took away Ms Schiavo's liberty to have her wishes, as determined by the concerned courts of law, respected in her manner of dying.
It might well qualify.
At least one conservative jurist found the law deficient on a number of other grounds, as well:
http://www.acsblog.org/separation-of-powers-the-constitutionality-of-terri-schiavos-law.html
Have you read the testimony the court used in determing Terri's "wishes". Even if the Schiavos testified truthfully about things Terri actually said, there is no way any reasonable person could infer that Terri made her statements with the knowledge and intention that those statements could result in her being fatally dehydrated.