Kirk's backsory was informed by Diane Carey's old novels Final Frontier
(no relation to STV) and Best Destiny
. In them, George Kirk is a security chief of Starbase 2, having taken a post just a week's shuttle ride from Earth rather than a deep space assignment on a starship. Winona (who in this version was never part of Starfleet) is a stay at home Mom for James and Sam.
I imagine something similar came about in the canon Prime-Trek universe.
What I'm curious about is: Who was Sam with while George and Winona were on their Kelvin mission?