how can someone get remoted as medical power of attorney if they are sick with illness and trying to tend to affairs of dying brother

Unfortunately, a power of attorney has to be signed when the grantor is in a competent state of mind.  If he is in and out of saneness, he could sign when he is aware of the situation.  However, a power of attorney ends when the person dies. A guardian/conservator could be appointed involuntarily by the court.  This would allow the person to take care of the affairs once he/she is appointed by the court. It would appear that a will also needs to be considered.  If your father is aware of the extent of his property he may still be able to do a will.