I don't think so. "Forcing" food down Terri's throat is equivalent to "forcing" food down an infant's throat. If the former can be lawfully prevented, so can the latter.
You've missed my point entirely. An infant cannot feed itself. A bottle must be inserted into its mouth for nourishment. Terri is no more being "force fed" than a baby is when receiving a bottle. What's happening to Terri is no more torture than giving a baby a bottle.