A Power of Attorney only gives someone the ability to deal with your finances and assets. It does not give a person the right to make medical decisions for you.
British Columbia has passed legislation that allows you to appoint someone to make medical and personal care decisions for you and to outline your wishes if you are suffering from a terminal illness. This new document is known as a Representation Agreement.
The law states that if, in an emergency, you are unable to make medical decisions then your spouse is allowed to make those decisions for you. If your spouse is unavailable, this falls to your children, and if your children are under age and your parents are still alive, then your parents become your medical decision-makers.
If you anticipate that your children would have difficulty agreeing on your medical or personal care, you may wish to appoint one or two of your children to be the prime decision makers for you. You may also appoint your spouse as your personal representative, but allow a third party, such as a child, to act as a monitor to ensure they are acting in your best interests. You may divide the responsibilities, appointing one person to manage personal care decisions such as diet and hygiene, and another to make major health decisions.