Texas requires that you have a separate power of attorney for your medical needs. Your durable power of attorney allows someone to take care of your business assets. A medical power of attorney allows you to authorize someone to take care of your health and well being.
The responsible person you select will be able to talk to doctors and medical institutes and make medical decisions for you when you cannot make them for yourself as long as the decision is not between life and death. That decision should be left in your hands.