Best question I’ve seen in awhile in a support ticket.

Yes, indeed, she did get Gutenberg’ed. Her entire layout became a weird white screen with some blocky blocks and text.

Simple solution: Install Classic Editor plugin. Then activate it. Nothing else required. Over 5 million installs and a 5 star rating. Gutenberg, by contrast, has 200,000 installs and a 2-star rating (at present time). The numbers speak volumes. And yet, in their ultimate wisdom, Automattic has decided that it needs to be part of the WordPress core. Go figure!