They also get lost in the GUI in my experience. Too many things that are clickable or possibly clickable, too much information on the page and they get overwhelmed.
With CLI, you do have to remember commands and compose things, but somehow it is easier for them. I am actually always surprised by this. More people should try to teach their older relatives some CLI magic.
One reason being they could go back and look at previous actions.
Another being how you could only do one thing at a time, and put other stuff on hold (and was reminded if you wanted to shut down).
The author likened the latter to putting a bill somewhere visible as a reminder to pay it.