RE: How much should we teach?
I can't add a whole lot to what already has been said.I do think that as long as he has the interest you never stop.If he loves it as time goes by your interaction will become more of a sharing instead of all the information going from you to him.He will start bringing things to your attention that will be his interpretation of what he is seeing.
From an establishing an independence point of view,I think you have to go with your gut on that,is he so well schooled and responsible in his climbing of tree's and his use of the proper climbing belts and safety belts,the handling of broadheads etc.
I would be inclined to be in the same tree with him for quite a while,you can use the excuse of videoing his hunts so it doesn't feel to him like you are babying him.He will let you know when he is ready,I think it will happen naturally.
He is lucky to have a dad that is so involved with him,that is about the best investment of your time that you can make!