Kirk (in the original timeline) may well have called George Junior "Sam" to distinguish him from his father. Indeed, I share my father's name, and have been known by my middle name since birth. I didn't even know my first name until the first day of Kindergarden, then the teacher called someone with my last name at roll call.
Since in the alternate timeline, George Senior is dead, Junior is the only George Kirk left.
As for the "I lost a brother" line in Star Trek V, I see that as an oversight on the writers. They simply forgot about Kirk's older brother George - I mean Sam - I mean... well, you know what I mean!
Since in the alternate timeline, George Senior is dead, Junior is the only George Kirk left.
As for the "I lost a brother" line in Star Trek V, I see that as an oversight on the writers. They simply forgot about Kirk's older brother George - I mean Sam - I mean... well, you know what I mean!