kctibs, I was one of those kids. I taught myself to shoot, and my solution was shooting right handed with a dominant left eye, I climbed over the stock. It worked into adulthood, until I started shooting military rifles, and then things had to change. Although ambidextrous, I am stronger right handed, so I trained myself to close my left eye.
I went on to become a police range instructor, a SWAT team leader and instructor, and never shot below Master lever for 20 years. I NEVER shot below 96% of 100 for that time on scoring runs.
If you son is strong right handed, but left eye dominant, I personally would train him to right eye. You can start with a patch, and work your way down. Also have him do hand exercises where he lines something like the end of a pencil with an object in front of him, while both eyes are open, and he can shut either eye to see which eye he used. He can train himself this way to switch eyes, with minor adjustments. And yes, it can be done even when shooting pistols and revolvers. Good luck