If it was only used as a “just in case because no one ever knows might happen to even a healthy person” situation then it would be fine.
But if you knew that someone was actually at risk because of known risk factors then I agree.
I think things got a bit confused here.
the OP was about sending a notification to someone outside of your own household which is monitored by HA. presumably that person wouldn’t have a way for them to interact with your HA and respond to a notification within HA itself.
Like in the apartment complex situation someone had to “notice” that someone else wasn’t in a “normal” condition (hasn’t been seen, etc) and someone outside the household would check on them.
In this case HA would do the “noticing” and contact someone to check on you.
When I added that last bit above about notifying you if a call was made so you could expect a response I changed the assumption that the person being contacted is outside of the monitored household and not linked in to the monitored persons HA environment.
in one situation you are being monitored by HA. In the other you are the one HA is calling about the monitored person.
…And me reading the above again I’m not sure that I have done anything to minimize the confusion tho.
So, yes, if both parties are within the same HA environment and can both send and receive notifications, etc from HA then a wait_for_trigger from a response to an actionable notification would work.
But if the contacted party is outside the HA environment then there’s not much that can be done if the monitored person doesn’t reply to a call back check-in aside from someone going to physically check on that person.
I use a similar system right now.
My wife stays home alone quite a bit when I’m at work and she was concerned about what she could do if something happened and she couldn’t get to her phone to call someone (911, one of the family, etc).
So I set up my Amazon Echo speakers to listen for a key phrase (Alexa, I need help) which sets off a routine that will have HA call and text everyone in our family (me, my wife, our kids) using Twilio to say that someone at our house needs help and then they can take appropriate action (come over, call 911 on our behalf, etc).
Is it like calling 911 ourselves? No. But it is a backup in case the situation is such that a real 911 call can’t be made. I have recently learned that Twilio can actually make direct 911 calls but I haven’t figured out how to do it yet or if the local emergency services would actually respond to a robo-call.
But if no one answers the call or sees the text then there isn’t much HA can do about it.