I need to disable some fields based on the checkbox. If the checkbox is checked, I need to disable some fields, not hide them. When the checkbox is selected the fields need to be grayed out and not authorable.
Yes, it's totally possible, please have a look at[0][1].
Be careful, through and explain to your client that there is 0% guarantee on next AEM Release the component you are using will still work and this will increase maintenance burden on your project.
Would be perfect if Adobe did provide us a set "stable" API's to control behaviour for Granite UI elements and we did not have to mess with Jquery selectors and setters.