Yes. They're signed out of your tree straight away, and their other trees carry on as normal. Their card stays on the tree as part of the family record – removing someone's access doesn't remove them from the family. If you just want to stop them editing, you can change their rights in Settings instead.
Where to find it
Settings, bottom row, far right
Only people with the "Settings" tick.
On a phone: if the menu is tucked away, press ☰ Menu (top left) first.
Still stuck? Talk to a real person: send us a message, or email support@mywholefamilytree.com