my host is updating so they are down. do I need to do anything on Cloudflare’s end or do nothing. this is not Cloudflare related.
No, you don’t need to do anything, unless they change the IP address of your website as part of the update. If this is the case, then you need to go to Cloudflare dashboard > DNS and in the records where it says that it points to x.x.x.x (old IP address of your website), change the IP to the new one.
What you could have done before they turned the server down was to set a page rule with both Cache Everything and Always Online settings, and Cloudflare would still allow visitors to get static pages in your website, whenever possible (pages not dependent on login status).