Go to Google home settings and invite family members to join the home.
And they will appear automatically in nest. They will then have to
download nest app individually on their phones and join with same email
where you sent them invites
Why bother creating a new app Google home to control some of the nest
products. When you have a nest app? They should have renamed nest app to
Google home instead making a half baked app like Google home. Which only
control some nest products