They had bodily autonomy at the time they made the decision. They gave it up in exchange for receiving the treatment, and thus no longer have it; the "don't have bodily autonomy" phrasing is accurate. The fact that this was a voluntary decision which they were perfectly entitled to make does not mean that it wouldn't have been better if they had another option which allowed them to receive the treatment without giving up their autonomy.

Merely not being provided with documentation for how the device works and how to control it I could overlook; after all, we don't even have that for the bodies we're born with. Everything we know about how we work is reverse engineered. But the patient is most likely prohibited by law from reverse engineering or otherwise tampering with this device which is now part of their body, and that I cannot condone.

Voting with their feet/wallet/choice of medical procedure? We have rights and regulations because these individualist methods have again and again been proven ineffective.