Hi. I'm not related to this family.This might be Samuel in 1860:
1860 United States Federal Census about Saml F Decoteau Name: Saml F Decoteau Age in 1860: 5 Birth Year: abt 1855 Birthplace: Louisiana Home in 1860: East Baton Rouge, Louisiana Gender: Male Post Office: Baton Rouge Household Members: Name Age A D Decoteau 40b. 1820 LA; Laborer Mary D Decoteau 42b. 1818 LA Antwine Q Decoteau 11b. 1849 LA Eliza J Decoteau 7b. 1853 LA Saml F Decoteau 5b. 1855 LA Sarah A Decoteau 2b. 1858 LA
According to a tree on Ancestry, Samuel's parents were Antoine Dorgieville Decoteau & Mary Ann Lloyd.Antoine's parents were Francois-Xavier Lefebvre dit Descoteaux & Marguerite Parent.However, according to this tree as well, Samuel married Telitha Ann Rouse 25 Feb 1876 in East Baton Rouge.They had three children: Albert, b. 1878; Alma, b. 1880; and Hattie Mary, b. 1886.
This would be that family in 1880:
1880 United States Federal Census about Sam Decotaul Name: Sam Decotaul [Sam Decoteau] Age: 22 Birth Year: abt 1858 Birthplace: Louisiana Home in 1880: 8th Ward, Ascension, Louisiana Race: White Gender: Male Relation to Head of House: Self (Head) Marital Status: Married Spouse's Name: Telapha Decotaul Father's Name: Dorgeville Decotaul Father's Birthplace: Louisiana Mother's Birthplace: Louisiana Household Members: Name Age Sam Decotaux 22b. 1858 LA; Laborer Telapha Decotaux22 -wife- b. 1858 LA Albert Decotaux2 -son- b. 1878 LA Elma Decotaux 9m -dau- b. Aug 1879 LA Dorgeville Decotaux68 -father-widower- b. 1812 LA; Works in Garden