I don't have a Ring doorbell but I have two Ring stick-up (battery powered) cameras that I like, but I don't answer my door through them. I'm not sure if the Ring doorbell works exactly the same, but I think they are similar. As has been mentioned there can be a small delay in uploading and accessing the video, so for that reason I'm not sure how well it would work for immediately answering a doorbell. It would let her know that a package had been left and any other motion that was detected. You can also do a live view at any time.
The notification of motion detection is very fast. It's just the video upload that sometimes has a short delay. The other night I had a coyote in my driveway again and the notification was very fast. But by the time I went to the real time video, he had gone. However, the video had recorded him immediately and I can view that at any time. I just had to wait a minute (or half-minute?) to see him, even though I instantly knew that some motion had been detected. (I hope that makes sense!)
I also have one Wyze camera, and my Rings are more dependable about detecting and notifying me of motion. Part of the difference may be the placement of the Wyze cam so I'm not knocking those. I just like my Rings better, but of course they were a little more expensive than the Wyze.
I don't do the community or social media stuff. I don't understand the comment about not being able to opt out of it. You can sign up for community event notifications, but you don't have to, and even if you did you don't have to post or share anything of your own. As for Ring working with police, if that's true I'm fine with that. I'd also rather my videos be stored in the cloud than in the camera, because the camera could be stolen and the video would be gone with it if it's stored inside the camera. Some systems store data inside your home, but I think they are more complicated and expensive. I am not a techie so take anything I say with that in mind.
Bottom line, I like mine, but because of the short delay (which varies) I'm not sure how well they would consistently work for answering the door. Maybe the doorbells work a little differently?
Regardless, it seems that some type of camera system would be helpful to her in several ways plus provide some needed security. Good luck with helping her find something that works for her needs.
Edit to add: I have the Ring apps and can check my cameras on my iPhone, my Mac Air laptop (which I'm on now), and on my Fire tablet. I don't have an iPad. They also work with Alexa by adding them under devices in the Alexa apps.
