Thanks @xmasbaby0
Most likely it will work the way you have described.
But on the other hand, I assume IL asks this question in order to avoid one person's IL exemption being used twice. If both the parents and the child lives in IL and files IL tax return, then everything makes sense.
While for my son's case, the logic is not very clear why he should loose his IL exemption.
Thanks again for your help!
Geng
