I hate those kinds of dreams! Or the ones where you wake up and still "see" whatever is in your dream! I do that w/ bugs (the insect kind) alot and it freaks me out, i look like a moron cuz I sweep and beat my pillow trying to get them off LOL.
I agree that it was probably not a predicting dream. You said he is "due to be sick" your subconcious knows that and that could be why you dreamt it. Just keep up w/ being sanitary and you will be fine. Also you haven't been sick since age 10 and he's been sick every year so you have been fine years that he has been sick so if he does get soemthing at some point (not because of the dream tho) than you will still be ok! Hope this helps!
\"As soon as you trust yourself,you will know how to live.\"
Johann Wolfgang von Goethe
\"Do not anticipate trouble, or worry about what may never happen. Keep in the sunlight.\"
Benjamin Franklin