Unfortunately, detecting that a device that is no longer sending data to SmartThings is not a feature of ST_Anything. There is a “Last Updated” field on every ST_Anything child device which at least lets you know how old the data is.
The feature you are probably referring to in ST is called HealthCheck. This feature has been more trouble than it is worth for many users, myself included. I simply disabled it in my ST Phone App. Way too many false positives.
There are some SmartApps that do a great job of monitoring your devices and sending you a notification if that device has not updated over a certain time-frame. The one I use is called “Device Monitor” by @erocm1231. You can find details about it below.