No...he should not file for IL in that situation.....as long as only IA is listed for box 15 on his W-2, and only IA taxes were withheld.
IA and IL have a reciprocal tax agreement, whereby a resident of IA, can work in IL and only pay IA taxes.
An IL resident working daily, or temporarily in IA gets the same treatment for their IL tax return, as long as only IL taxes were withheld, and only IL is in box 15 of their W-2.
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He and his employer need to be careful though...if he spends too many days/nights in IL, then IL may start to consider him as an IL resident, and want to tax all of his income for the time he spent in IL....the usual break-point is staying in a state more than 183 nights (but I have no idea if IL uses that limit or not )
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
