Reddit mentions of The Witchery of Archery

His form isn't terrible, it's different-- it's an old school style developed more for a hunting situation where you likely had to take a shot from uneven ground, or from behind a bush, or from a tree, or prone, or on your back. Longbow hunting forms focus mostly on versatility and being just accurate enough to put an arrow in the kill zone

When it comes to longbow shooting, there are certain things that translate from Target shooting:

1. Solid footwork-- as Byron Fergison says, every good shot is built from the ground up. The longbow stance is a little wider than a target stance but you still need to be in line, at least for standing shots
   
   
2. Consistent draw-- hunting longbow stances have a different full-draw-form, but their draw needs to be consistent every time
   
   
3. The follow through-- hold the bow steady until the arrow hits the target. No flinching, no plucking, hand locked against the face (his anchor might be a little different. I'll get more into that later)
   
   
4. Consistency in grouping/shooting
   
   
5. ENCOURAGEMENT-- a positive attitude is a must for anyone who is learning instinctive shooting
   
   
   These are things that will not translate from target shooting:
   
   
6. The swing draw-- longbow shooters with heavier bows will have a different "closed" form than a target/recurve archer (think: upright olympic rifle stance vs. military combat stances).
   
   
7. You don't need to hold the bow at draw for as long (because the swing draw, done correctly, will put you in the correct form)
   
   
8. bow canting: It's personal preference. More cant = better field of view = more focus on the target. However much he cants the bow, make sure that his eye is in line with the arrow shaft. Each longbow shooter has their own optimal angle for bow canting, he'll discover it on his own after a while
   
   
9. The anchor point: I'm not sure what you use as an anchor point, but most hunting longbow forms anchor above the chin, usually pressed against the face. This gets the arrow closer to the eye and allows the archer to either consciously or subliminally sight down the arrow. The anchor point needs to be fixed for hunting forms-- no string walking or anchor point raising/lowering, just a consistent draw and anchor each time
   
   Archers you'll want to refer him to:
   -Howard Hill
   -Fred Bear
   -Will Young and Saxon Pope
   -Byron Ferguson
   
   Books:
   Hunting the Hard Way (Howard Hill):
   http://www.amazon.com/Hunting-Hard-Way-Howard-Hill/dp/1568331460/ref=sr_1_1?ie=UTF8&qid=1412751131&sr=8-1&keywords=hunting+the+hard+way+howard+hill
   
   Become the Arrow (Byron Ferguson):
   http://www.amazon.com/Become-Arrow-On-Target-Series/dp/091330509X/ref=sr_1_1?ie=UTF8&qid=1412751154&sr=8-1&keywords=Become+the+Arrow
   
   Hunting with the Bow and Arrow (Saxton Pope):
   http://www.amazon.com/Hunting-Bow-Arrow-Saxton-Pope/dp/1497520010/ref=sr_1_1?ie=UTF8&qid=1412751194&sr=8-1&keywords=Saxton+Pope
   
   The Witchery of Archery (Maurice Thomspon):
   http://www.amazon.com/The-Witchery-Archery-Maurice-Thompson/dp/1446528197/ref=sr_1_1?ie=UTF8&qid=1412751234&sr=8-1&keywords=witchery+of+archery
   
   There are many videos on Youtube of Howard Hill, like this one:
   https://www.youtube.com/watch?v=zo8UZneuggE
   
   and some very good instructional videos:
   https://www.youtube.com/watch?v=98fuYYD5LOM
   https://www.youtube.com/watch?v=nJKOZ6KfRRs
   
   and some very bad ones too... Stick with the videos of people who were famous archers. Howard Hill is my favorite for reasons you'll see in the Cavalcade of Archery film, but anyone who's an established trick shooter or a renown hunter can also be trusted sources of knowledge
   
   The key to longbow shooting is that there is no one right way, there's only what works for the archer. It's a lot of experimentation, a lot of failing, but eventually he will learn what will work out best mechanically for him. He will need to take note of the different forms (including target style shooting) and take pieces of what works well for him-- just don't be offended if he doesn't do exactly what you want him to do because the longbow and the recurve are very different beasts.
   
   But above all, encouragement and always having a positive attitude is going to be the best thing. If he's self taught, it's likely he already knows how to take pieces of different forms and adapt it to his own needs (so yes, yo should definitely be teaching him Target shooting form stuff), but having someone to bounce ideas off of or even note when their elbow is low or they're shaking is a huge help, but above all encouragement is going to be the best thing you can do