Hello and welcome to e health forum.
Determining the need for continuing life support systems - is difficult and ambiguous in the following situations.
1. in critical conditions where the survival of the victim without such help, even after considerable duration of supportive therapy, is questionable ; or
2. in patients who may have suffered severe organ damage resulting in a possible low quality of life post recovery.
In such situations doctors usually take into consideration the wishes of the patient (Expressed directive, living will ) or by relatives (with Health power of attorney).
Feeding tube - is a treatment procedure to prolong life, and can continue as long as the life support systems are in place.
You might consult your doctors for proper advice and further course of action.