No, this won’t work with Things.
If you have only one Thing you want the status from, you can just create a rule that triggers based on status changes of the Thing. In the action, create a timer to send the alert after the desired amount of time and cancel the timer if it comes back ONLINE before the timer goes off.
Or you can create an Item and use Debounce.
If you have many Things you want to do this for, you can use Thing Status Reporting [4.0.0.0;5.9.9.9] which will call a rule you specify which can then look for those Things you care about and set timers as described above. Or update Items and use Debounce.
But to use Debounce you’ll need two new Items per Thing. One to represent the raw status of each Thing and one to represent the debounced status of each Thing.
Yet another alternative would be to use Threshold Alert and Open Reminder [4.0.0.0;5.9.9.9] instead of Debounce. But you’ll still need to create at least the one Item to represent the Thing’s status.