The 1840 census for Eliphas Preston shows 1 male between 40-50 & 1 female between 40-50, i.e. no children.
hHs neighbors are Jeffrey Preston, Moses Preston, Thomas Preston all with young boys under 5. Thomas Preston with 1 young girt under 5. Another neighbor is Shadraoh Preston.
I think it likely that Thomas Preston in 1840 had 2 boys and 1 girl under the age of 6 and he was the brother/cousin of Eliphas Preston. By 1850 he had died (?) and his children were living with Eliphas.