Hi Mopar, if you can, schedule a few lessons with a PGA golf instructor before he gets too far down the road.

In general, now would be a good time to start building a little pre-shot routine while practicing and playing. Your son needs to learn to build his stance the same way every time. If he is incorporating a practice swing utilizing the same target line and lie is a good idea. After the PS have him move into the ball by placing his club behind the ball then move into it with the body. He should bend from the hip sockets just enough to allow the arms to hang normally straight down tension free. For the longer clubs FW,s and Driver the arms will extend outward more; but, still not a lot as he will be standing a little taller with less bend at the hips. All your practice sessions should be done with a practice grid set up with clubs or something else defining the heel, hip, shoulder line and another the ball target line.

Some things that remain fairly constant with various clubs are: the angle of the shaft to the arms when viewed from behind. The heels, hips, and shoulders parallel to the ball target line. The spine angle should be relatively straight, chin up; but without tension. When viewed from across the target line looking face to face your son's spine should be angled toward the rear a bit causing the aft shoulder to be lower than the front.

These are a few suggestions to get started. I really think a few lessons would pay dividends.

Cheers, Bob