Assume that you, an ordinary type citizen without subpoena powers or superflous funds, and want to know if someone is alive or not. Nothing else, no history check, none of that stuff. Just one or the other.
The social security death index. You can google it, but I think you can find it at Ancestry.com. I check it every now and again to see if my ex-husband is still alive.
As a matter of fact, Homer wasn’t too far off. Or so it seems to me. When my father died, the doctor listened verrrrry carefully for heart beat and breathing. And then, as a last test, flicked his eyelashes with a finger to see if there was any reaction. And, yes, he held a small mirror to nose and mouth looking for condensation. Sort of grisly.