Additional suggestions.
Forgive me if you already know all of this or have experience. Others on the forum may find this interesting.
Proper stance for Trap Shooting. I am right handed and the following is the stance that I prefer. Using the image below as a reference.
1. Stand with the majority of your weight (70% give or take) on the front foot. In my case, my left foot.
2. My feet are spaced about shoulder width apart. I prefer to point the toe of my front foot at the center point of the flight pattern of the bird (not the center of the Trap House). On station #1, that would be approx. 8-10' to the left of the Trap House. Station #2 would be approx. 3', station #3 would be center, station #4 would be 3' to the right and station #5 would be 8-10' to the right.
3. After shouldering the weapon and prior to calling for the bird, I aim the weapon at the top edge of the Trap House. For station #1, I use the top left corner as the aim point. Station #2, I aim about 1/2 way from the left corner & center. Station #3 is center and so on.
4. By using these set-up tips, it reduces the amount of rotation needed to get on target. The idea is to eliminate the need to twist the entire body. The body should rotate, as much as possible, only at the waist. The upper body (head and shoulders) should not rotate and the lower body (legs and hips) should rotate very little. If you rotate the shoulders to the left, it pulls the weapon in tight against the face and rotating the shoulder to the right pushes the weapon away from the face. Neither is a good situation.
5. With both eyes open as the target leaves the Trap House. Locate the target, follow in behind it, catch up to it and follow through it as you press the trigger. This should be done all as one smooth, fluid motion.
I hope this helps and, MOST of ALL, enjoy your time with your son.
If you position your stance at the center of the Trap House, as you can see, from station #1, a hard right bird is actually a straight away and a hard left bird would require twisting the body to the extreme left, thus causing poor form and , most likely, a missed target. The same is true, only in reverse, for station #5. I hope this all makes sense.
If you google "proper stance for trap shooting", you can find several sights that address that topic.