RustDesk
RustDesk is a powerful yet lightweight alternative to AnyDesk, or Teamviewer. It is, it allows you to remotely control a computer to help your grandparent which is stuck on a popup or because Firefox crashed.
Installation
You can just install it by using
# pacman -S rustdesk
It should enable the service automatically so that the server runs at start.
Running rustdesk
will give you the ID and the password of the machine. Note it somewhere, install the client on your personnal computer and you'll be good to go.