How to make checkbox disabled in CSS?
You can't style a disabled checkbox directly because it's controlled by the browser / OS. However you can be clever and replace the checkbox with a label that simulates a checkbox using pure CSS. You need to have an adjacent label that you can use to style a new "pseudo checkbox".
How do I make a checkbox read only?
Disable action will make the checkbox is read only, but this lead to checkbox value will not store in the session, so you will need to do some walkaround such as creating temp item to hold the value.