Compromised password alert.

Hi Cleetus that means that most of your dad’s password needs to be update because the system detects that they are easy to guess in case if someone try to access them and I highly suggest you to tell your dad to change the password in the websites that are storage in his devices marked with a red circle 🔴 in your Mac , iPhone or iPad if all are using the same iCloud account

If you legitimately have accounts at the named domain then log in to account in Safari by typing domain name (as opposed to using a link or a bookmark) and change the password.

I'd also suggest getting a password manager such as 1Password. It will create complex passwords that are easy to change if necessary. You only need to remember one password to get into 1Password. Get it? ;-)