A healthcare power of attorney (HCPA) is a legal document that allows an individual to empower another person to make decisions about their medical care. A healthcare power of attorney refers to both a legal document and a specific person with legal authority.
Ask them to sit down and to have a calm mind. Show them thsat you are responsible and state the facts. Keep in mind that it is hard convincing a parent you are responsible and that they always stop you from talking and state their point so when you're talking tell them to listen because you didn't come to them to have an argument.