Frightening questions. No good answers.
Re #2 The hospital was compelled to notify the parents when the pregnancy was discovered. The hospital could not end the pregnancy without authorization from the girls leagl guardians. No doubt they urged the parents to authorize abortion as it was considered a high-risk preganancy due to her condition, but as Catholics, they refused. Even if PVS patients rights are eroded as you suggest, the guardians still have rights and decision authority.
My husband and I remember the case only to well.
If, however, the patient was not considered to be under the auspices of the Constitution, my thinking is the hospitial would simply counter with the abortion being considered part of their protocol for the welfare of the patient.
Once guardians give approval for the day-to-day protocol to be decided by the hospital, an entirely new grouping of what you and I would call 'abuses,' would most likely be sanctioned by the likes of judges such as Greer.