OK, well, let's assume this writer is correct, and Terri really isn't "there."
In which case, "letting her go in peace" doesn't have a lot of meaning either.
In other words, no harm is done by continuing to feed her, except the continued expense of her upkeep. Schiavo was given the money for that. Granted, he's probably blown it all by now, but I'd be willing to bet the funds for Terri's upkeep could be found somewhere.
If she isn't there, then she doesn't give a damn whether her body is maintained or not, so there's no harm in maintaining it, whereas there could be great harm in failing to maintain it: the murder of a human being. In this case, it's... money on one side... versus... the (arguable) life of a human being on the other side.
Undoubtedly I don't know all about the case, but from what I at least think I know, it seems clear to me where Mr. Schiavo's priorities lie.