A kisser button can be a good start. But what I have found in the past it is practice, practice, practice. But, make sure you or the father of this boy are helping him with repetition. Ensuring he is pulling back to the same point. If he is not using a kisser button to help with an anchor point, is he using a knuckle against a cheekbone or thumb to a spot on the face, etc. Whatever it is make sure he does it the same each and every time. Then make sure he is holding the bow the same way, and his release (if he is using one) is fastened the same way and he. Look at things like that and then everytime he shoots watch his form and help critique him and before he shoots give his form a good look over and go through a mental checklist (but announce it to him what you are checking and if it is good or not). That way he learns what you are looking for and after a few dozen times or maybe hundred times he will start to do all this on his own.
Also, try to have him "blank" shoot to get the form down. Don't have him aiming at a specific target at 20 yds or 10 yds or whatever distance you choose. Instead, if you can get something large to shoot at (around me I can get to a farmer's house with round hay bales) and then let the person shoot into that. At this point you don't care where he the arrow is hitting at, but rather you are trying to develop form and muscle memory. This way the boy will be focusing on form and shooting rather then aiming.
I have found with young kids it takes them a bit to understand things such as form. Just like trying to teach a kid to bat or throw a ball properly. If you can break it into small steps or pieces I find they learn it quicker.
Some good info.
I used to teach kids at my local club for several years.
Know a few things. Kids hate advice from their parents. Have another parent tell your child and they will take it to heart.
Start simple. Does the bow fit the child? Is he over bowed, weight wise? (watch for him "skying" the bow to come to full draw. BAD. He should be able to pull back with bow arm horizontally extended) Look at the draw length? Many times they are set too long. If they are shooting a Genesis, see if you can install a set of draw stops. Preach foot work. Feet should be ~ shoulder width apart and toes should line up with target face. (Lay arrow on the ground at tip of his toes, arrow should be pointing at target.) They should be relaxed prior to drawing back the bow and through aiming routine). WATCH HIS BOW HAND. A riser should be lightly held, not gripped like he is trying to choke a duck! (Gripping riser can cause left/right issues or forearm slap. OUCH)
You will likely need to nibble at these topics. The shot process is a checklist every time you pull an arrow out of the quiver.
Check Feet
Pull arrow from quiver and nock.
Address target (Acquire aiming point)
Draw back and settle on checkpoint/checkpoints (Kisser to nose, thumb settled into jaw bone (If shooting release) etc)
Focus on aiming point and begin shot sequence.
Follow through after the shot. (Bow arm stays extended and toward target, release hand naturally comes straight back etc) No peeking or violent explosions of body position after shot.
Repeat. And practice repeating.
When they are tired or they start going backward, stop them. (Difficult to do) More is not necessarily better. They need to repeat and reinforce good shooting sequences, not repeat and imprint on bad sequences.
Now I need to heed my own advice! Good luck!
