After so many years, it would probably take a downright miracle to cure you, especially of scleroderma. They know that.
They just need to follow up to make sure you aren't somehow back to work full time, without having let them know about it. Just fill out what they ask for and send it back in. If they need any more info, they will let you know.
Miocean's situation is a little different, as they typically review people who have had transplants, or major life-changing treatments, to see if they are now cured and able to return to work full time. But unless you've enjoyed some tremendous curative treatment for scleroderma that has had you bouncing back to work full time, you hardly have anything at all to worry about...except, unfortunately, still being sick, and still not being able to work full time.