I think Lois is his sister.
Source;"Connecticut Births and Christenings, 1649-1906", database, FamilySearch (
https://familysearch.org/ark:/61903/1:1:F7WN-1VL : 7 January 2020), Lois Griswold, 1771.
Connecticut, Vital Records
: Lois Griswold
: Birth 27 April 1771 Wethersfield, Connecticut
: Father Simeon Mother Mary Ann
Source: "Connecticut Deaths and Burials, 1772-1934", database, FamilySearch (
https://familysearch.org/ark:/61903/1:1:F7KQ-P47 : 16 January 2020), Lois Griswold
Connecticut Deaths and Burials
: Lois Griswold
: Death 14 Sep 1840
: Ref ID v 56 p 74
: Age 69 Birth (est) 1771