If his residence for the whole year was Illinois, and only Illinois state income tax was withheld on the W-2 , IE no Tennessee withholding and no Tennessee wages on the W-2 , then I do not see why you would have to file a Tennessee return... It doesn't matter what state the employer is headquartered in... Just my opinion... Hope this helps
we have what is called the Hall Income tax......which is a tax on certain non-bank interest, and most dividends, and capital gains distributions from mutual funds There is NO state income tax on earned income (w2s, guaranteed payments, self-employment earnings, etc). This has been in effect since 1929. was 6% forever, but the legislature enacted a 1% annual reduction in the tax rate, til it goes away... which is 2021. this is the last year of it...1%.
if you see a w2. with TN Income tax withheld....then something very fi$hy with that employer accounting $y$tem.