You can change how long a phone rings for. Talk to her telco for both landline and mobile.
In my experience, if someone doesn't want to answer the phone, strapping it to their arm is unlikely to make any difference and in my experience they're more likely than not to leave it on the charger.
Long battery life and tiny battery are on opposite ends of physics. Pick your poison.
Health monitoring is unlikely to be transmitted to emergency services, except iOS fall detection.
iOS and Android are both tracking as much as they can get away with.
Remote management is likely only with devices used in corporate settings.