In order to have members of your site receive calendar alerts for events in your trees, describing their relationship with other members, you should associate them to people in your family tree.
To associate a member of your site to someone in the tree:
Log into your site. From the Home tab click on the Site Members section.
Go to the name of the person who should be receiving calendar alerts.
On the right side of the screen, select “More” and select “Fix relationship”.
In the field that appears next to the person’s name, start typing the correct name and select from the list of names that appears. Click “Apply” to save.