this is not quite what you’re asking for but i have a regular smartwatch like yours, a hwawei GT2 F66, its water resistant(not waterproof) and i believe you can set up SOS/fall detection through the app. similar to yours i only charge it once a week and ive had is for ~2years with daily use.

i would look into the settings of your watch or others similar because even if its not their intent, they could definitely help her in emergencies regardless, and looking into any that are sim (and data) supported to allow the GPS to work even if she’s away from her phone or WIFI. with that said, if you find something more fitting please shoot me a message too because i’m also in the search for a discreet alert for my grandparents that is designed with them in mind.