George left a will, and all the names mentioned confirm the relationships. From Ancestry.com:
Name: George Smith
Gender: Male
Residence Date: Abt 1724
Residence Place: Lyme, New London
Will Date: 14 Nov 1724
Probate Date: 14 Nov 1724
Probate Place: New London, Connecticut, USA
Inferred Death Year: 1724
Inferred Death Place: Connecticut, USA
Item Description: Probate Records, Vol A-B, 1675-1725
Others Listed Relationship
George Smith
Rachel Smith Wife
Matthew Smith Son
George Smith Son
Thomas Smith Grandson
Matthew Smith Grandson