Is there a way, by which an airline or ATC would be alerted, if both pilots are asleep or incapacitated? There are various questions around, which deals with what happens if both pilots are incapacitated, but my question is different.

I want to ask, is there a way by which an airline or ATC is alerted that both pilots are asleep or incapacitated, more like a camera which tracks eye movement, which would alert the pilots or cabin crew or ATC.
No there isn't. The only indication ATC has is if the pilot doesn't respond to radio calls but that can also be because of other issues like a radio malfunction.

There is not much ATC could do anyway if pilots are non-responsive.