we can not see your return. Qualify for what? you can't use him as a dependent to file as head of household because you are not related. he also wouldn't qualify you for certain credits. maybe that's what Turbotax was referring to when it said he didn't qualify. perhaps your income is too high to get the other dependent credit
The credit for other dependents is a non-refundable credit. It can reduce or, in some cases, eliminate a tax bill but any unused portion is lost.
here's a link to IRS tool to determine if you qualify to get the other dependent credit (max ($500)
https://www.irs.gov/help/ita/does-my-childdependent-qualify-for-the-child-tax-credit-or-the-credit-f...
