Christians believe we must respect life until its natural end. From everything I have heard, this poor girl's life has already reached its natural end some time ago. She is being sustained by machines and she would quickly pass away if not for very active mechanical and medical support. I don't believe this is a "right to life" issue, but of course am willing to be corrected.
Jahi McMath's situation is radically different from that of Terri Schiavo. Mrs. Schiavo was an otherwise-healthy woman with all systems working just fine, except for her severe brain injury which apparently shut down her cognitive capacities. She was not "brain-dead" nor even dying, not in pain, able to breathe and maintain homeostasis on her own. She was deprived of food/water in order to kill her--- and that was murder most intentional.
In Jahi's case, she suffered cardiac arrest and total, irreversible death of the entire brain, including brain stem, weeks ago. There has no been any blood circulation to the brain or any electrical activity in the brain for weeks. They are simply ventilating a corpse.
This is the unanimous finding of the hospital doctors, and the outside doctors who were chosen and brought in at the parents' request.
Her parents need to remove the tubes and wires and give their much-loved daughter's mortal remains a respectful, prayerful interment.