This ultimately depends on state law, but the hospital probably did not violate any rules. The medical power of attorney or health care proxy empowers the person appointed to make medical decisions, communicate with health care providers, and access medical records when the individual has been declared incapacitated. It generally does not impose any particular obligation on the medical provider to reach out to the health care agent. That said, it is almost certainly best practice for the hospital to do so.
While the health care agent in your situation may not have recourse against the hospital or doctor, she may be able to challenge the subsequent power of attorney and life estate. Competency is not a solid line where once you cross over you are incompetent at all times and for all matters. It’s more fuzzy. You may be incompetent to perform some activities, such as selling your house for the right price, but competent for others, such as choosing who should receive your estate when you die. You also may be incompetent while hospitalized because being there is disorienting, but competent when you return home. The competency test, therefore, is not conclusive, but would be important evidence to present to the court if you were to challenge the new power of attorney or life estate.
For more information on capacity requirements for executing estate planning documents, go here: https://www.elderlawanswers.com/capacity-requirements-for-executing-estate-planning-documents-12129