Yes. You will need to file Detroit City Taxes as a nonresident for his income earned in the city.
He needs Form 5119, City of Detroit NonResident Income Tax Return. See the link for more details: 2019 City of Detroit NonResident Income Tax Return Instructions.
Early on in the Michigan interview, you will be asked if you need a Detroit return. Check the boxes as indicated in the screenshot below: That the taxpayer needs a Detroit City Return and is filing as a Detroit Nonresident.