I think a lot of guitarists do consider your nephew's their "standard" way to finger a "G" chord. Stefan Grossman certainly tells you to do it that way. I always use it unless there are special demands. For example if I have to alternate between the "g" on the "e" string and the "d" on the "b" string, then I use what you call the "standard" fingering with my ring finger to handle the "d" and my pinky to handle the "g". As soon as I get through such a passage, I switch back to your nephew's fingering.

Murray