The MI death records show Jan 29,1899 as Paul's birth date. I find Paul in the 1930 census, St Clair Shores, Macomb, MI and Samuel (b. Mar 1854, MI.) in the 1900 census, Detroit, Wayne, MI., b. Michigan. Paul is shown as Napoleon P.Vezinaw (b. Jan 1899, MI) and in the household is Napoleon Leviellier as father in law and Annie Leviellier as mother in law. Both born Canada (French). Samuel's wife is shown born June 1861, Canada (French). Both of Samuel's parents are shown born Canada (Fr.)
I do not find any Vezinaw in the 1880 census however. this leads me to believe that because of the pronunciation the name may be spelled somewhat different according to what the census taker heard. I do find a Samuel VISINA in Detroit, 1860 census, b. Canada, ca. 1832, wife, Sophronie, b. Canada,with a Samuel there,correct age, b. MI. Siblings were August and Adeline so if that matches your grandfather's info this would be a match. In 1880 census, Detroit, there is a Samuel VIRGNAN, b. Canada, correct age, and wife Sophronie, b. Canada, correct age so they may be there in the census with many different spellings. Canada is where your search for your ancestors should begin.