What you can do to not display an error page when all web servers are down and showing unhealthy in health checks?
It will be nice to show a nice static web page that says something to the effect of all servers are down. This can be set up using an S3 bucket for static website hosting. After that upload, the index.html file, and that index page is what S3 will serve up. Then reconfigure the west secondary failover record to point it to the bucket. So, when anyone trying to browse to www.example.host should see the static web page hosted from the S3 bucket. Everything is the same except the secondary failover record for west which will have an S3 bucket as the target.