I have only just taken my 19 month old DS's dummy away from him - day 4 today. We had tried just cutting back and letting him have it at sleep time, but he was always asking for it and getting grizzly if he couldn't have it, also wanted it in the car or whenever we were out. So I decided that cold turkey really was the only way, as he just wasn't getting the 'only in your bed' thing. The first 2 days were difficult, but by day 3 he wasn't even asking for it anymore. Now, already, it's like he never had it. We took DS1 off the bottle when he was 2 and a half, and found the same thing; decided we were going cold turkey, as nothing else had really worked, and after two heartbreaking nights of tears he just seemed to forget about it and never asked for it again.
Once you have decided that you want to get rid of the dummy for good, and different people do it at different ages and for different reasons, personally I think you have to just take it away entirely. If your DS is still sick then I would wait until he is better like you said, and then bite the bullet.
Definitely the best thing we could have done...
[Edited on 15/02/2010]