Dan would like to get a doorbell that can not only notify his parents with video when someone is at the door, but can also unlock the door remotely. Rich says there are products that do one or the other, but not a lot that can do both. Ring is a great video doorbell, and he can view it remotely on a mobile device. Nest IQ has face detection, and could unlock the door. But he really doesn't want something fully automated. Plus, will Jack's parents really want to deal with the technology involved?
A two step process is probably best, and safer. He should get the Ring doorbell, and then have a remote that will unlock the door. He could also consider a dedicated tablet for it, so they always know where it is.
(Disclaimer: Ring is a sponsor)