If it were my mother missing, I would be going from door to door with her phone in one hand and * in another.
Besides the short range of bluetooth pacemaker connectivity, the device is not continuously broadcasting. It sends data to the monitoring device once a day or however the doctor programs it. If the pacemaker were continually broadcasting on bluetooth it would drain the pacemaker battery in no time. Current pacemaker batteries are suppose to be good for ~10 years.