My brother-in-law is currently on a feeding tube. It isn't because he can't feed himself--he, post-stroke, has the use of his right side, but it is difficult for him to swallow more than soft or pureed foods, and he is just beginning to be able to swallow water by spoon. He's on a feeding tube because he can't get sufficient nutrition or hydration by his own efforts alone. This may be the case with Terri.
Your brother-in-law and your family are in my prayers.