I can not find a connection between Jacob B. Parker and his wife Matilda who were living in Sumpter, Trinity County, Texas in 1860 and your Peter Parker. Jacob's brother William and his wife Louisa were also at Sumpter in 1860. Matilda and Louisa were Lewis sisters from Mississippi. William was the oldest and was born in Georgia. Jacob was born in Mississippi. In 1870, Jacob's widow and two youngest children were living with William and his family at Pennington in Trinity County.