If he is shooting 45# with a compound then I wouldn't get him anything over 35# in a traditional bow to start with. Here is a link to the bow I recommend for all beginners as it is a good bow for not a lot of money. Plus once he is ready to set up the poundage a little you can buy limbs and not a complete bow to get him there.
http://www.3riversarchery.com/Bows+R...X_product.html
Also make sure you start him with carbon arrows with feather fletching. Vanes and traditional bows just don't mix.