Sorry, in the 1870 census it states that Harriet was born in NC and for the children it looks like it says MY, I'm assuming it's short for Mississippi. (now that I look at it again, it might be Mis.) And I was getting ahead of myself, his mother is Harriet, sister is Rachel. I was going back and forth between too many screens sorry.
1870 census lists:
It is possible too, that Laura might be the mother.