If she was in a persistent vegetative state, would she even experience hunger?
I'm not sure there's a way to actually answer this. Medical science can make its best judgment based on observational data, but vegetative states aren't the same as brain death. There are still working nerve impulses and autonomic functions.
People who wake up from comas sometimes wake-up hungry, but that doesn't mean they felt hunger while they were unconscious. It also doesn't mean they didn't feel it.
I hate stories like this. The next of kin need options, so they're given options between suffering in form A or suffering in form B.