Medical professional giving my two cents here: physicians and healthcare providers are allowed, and in some cases even required, to disregard the expressed, voiced, or even written wishes of the parent if the parent's wishes would endanger the child's life. The classic example is with Jehovah's Witnesses: if a child of a Jehovah's Witness is getting surgery or suffered an injury with significant blood loss, the child will be given life-saving blood transfusions irrespective of the parents' religious beliefs or wishes.

This is not a breach of informed consent taken lightly, but physicians and other medical professionals will ignore what the parents did or did not consent to if it means that the child or vulnerable adult would die or suffer grievous harm otherwise.