In order to remove a member from your family site:
Please log into your account, and go into your family site.
Click on Home > Site Members. Here you will see a list of all your site members.
Click on the ‘More’ link next to the member that you would like to remove.
You will see the option to remove that person from your family site.
Please note that if you are not the site manager of the site, you will only be able to remove members that you invited to the site, not those that were invited by other members or the site manager.