I go to the Detroit area 3 times a year. If you had a relative buried there chances are they went to one of the catholic churches in the Detroit area.
If you know or have an idea of where/when your ancestor lived in the area I may be able to pinpoint the church.
The Burton historical collection at the Detroit Public Library the records of the catholic churches from Detroit on microfilm and they are the only depository of these records per an agreement between the archdiocese of Detroit and the Burton.
I will help in your research.