Have you already checked the census records for this person? I did a quick check and found several Fred Farwells in Michigan, but none in the city. Those that did come up were married, so if one of them are the guy you are looking for, that might explain why he wasn't around.

I also did a quick check of the Detroit city directories. I found one for the city of Detroit in 1916. I included the link below.

If you have a birth cert. for your grandfather, and it lists the parents' ages, that will give you an approximate birth year, which may help you to find the correct Mr. Farwell, or at least narrow it down.

1916 City Directory for a Fred T Farwell:

http://search.ancestry.com/iexec?htx=View&r=an&dbid=...