Decide whose phone owns it
An AirTag belongs to one Apple Account, and its anti-stalking features are built around that owner. If you live with your parent, make the AirTag yours: most days it is near your phone, so it behaves like any tag on a family keyring. If your parent lives alone, the tag is away from its owner almost all the time, whoever owns it, so expect it to act like a lost tag. If siblings share the caring, pick the one who lives nearest and share it with the rest.
Separation alerts
In Find My, Notify When Left Behind sends you an alert, in Apple’s words, every time the device sharing your location separates from the item, and you can add Trusted Locations where you can leave an item without an alert.[6] Apple built this so you do not leave your own things behind. If you live together, you may get an alert when your parent walks out with the tagged keys, but Apple does not describe it as a “they have left” alarm, and making home a Trusted Location may silence exactly the alert you wanted. Test it before you count on it. For knowing the moment a door opens, a door chime is made for that job.
Write the Lost Mode message now
If the tag goes missing, you can mark it as lost in Find My and add a message with your phone number. Someone who finds it can hold a phone with NFC to it and see your message.[7] Decide the words while you are calm. Something short and kind works best:
This belongs to Margaret, who sometimes gets confused. If she is with you, please stay with her and call her son on [number].
Use a first name only, since anyone who taps the tag can read it. A finder has to know to tap the tag, so it is never a substitute for wearable ID such as a medical ID bracelet.
Keep the battery going
The AirTag takes a CR2032 coin battery you can replace yourself, and your iPhone shows a notification when it is low. Apple says some CR2032 batteries with a bitter coating, sold to discourage children from swallowing them, might not work in an AirTag.[9] A yearly calendar reminder and a spare battery in a drawer take care of it.