Fasting vs. feeding tube

My dad is in the hospital. It is rather serious, he is mostly sleeping, and when they have tried to give him food, he wouldn't eat. He is on an iv, and for about a week, they were only giving him saline and a vitamin or two (B1, but earlier something else). They weren't giving him vitamin C because he had a kidney issue. I'm not sure if the fact that they have brought his calcium levels down to normal levels means that the kidney issue is resolved or not.
They have just started giving him iv nutrition, but they want to put in a feeding tube, and my mother has to decide what to do, quickly. This is not an end of life question. We do not want him to starve or die. My question is whether his long term prospects are better if he continues fasting* as he is, or if he would be heal more safely with a feeding tube. Back up from a study would be helpful for persuasive purposes.

* I do understand that iv's can interfere with the quality of a fast, but that is not a choice that I am being given. Tweet