ImDown is the name of this app.
If your parents' smartphone had not used for a while, it sends you an SMS.
Use it for health confirming of your parents living far away, etc.
If your parents don't use smartphone very much, make a charging stand on the refrigerator door. It's effective.
※For smartphones with battery saving mode,
Auto-startup and background services may not work correctly.
In that case, Please allow it yourself from the individual app settings on the system settings menu.