I would also suggest putting a few cheerios with the food you serve. I would start by putting them on top for a few days, then mixing them into the food so he has to "work" for them. This would also make them more covered with food and hopefully he gets a bit more into him other than just cheerios.

I wouldn't be worried about the other kids not getting cheerios but if your kids make a big deal out of it, do as playfelt suggested and give them a few. I am lucky that my dck's don't care (or maybe they don't even realize lol) that a couple of the others get different food. Sometimes they ask if they notice but I just tell them that "that's xxx's food and this is yours" and they don't complain about it.