Find a Grave has a Robert Hubbert buried at Elmwood Cemetery, Detroit, with Thomas Hubbert who died 10 Feb 1847 age 52 and Sarah Hubbert who died 10 Nov 1871 age 75. I can't read what it says on the tombstone, so I'm not sure whether it's the same Robert or not, but maybe related if not?
https://www.findagrave.com/memorial/...robert-hubbert