I'm a lefty and shoot right handed even with an ambidextrous pistol. I am also left eye dominant, but cross dominant shooting works fine for me. Oddly, I shoot rifle left handed.
I guess it's what works for the shooter. Most of us spent enough time playing with cap guns, airsoft, bb pistols, whatever that we have worked out the basic mechanics of what is comfortable. I'd suggest expanding upon what is comfortable for the new shooter before changing things up.
Just 2 cents...can't afford more than that.