Ok, my son, also 6, unprompted from me, I have never bow hunted, other than fish many years ago and for Alligator gar asked for a Bow and arrow and target pig for Christmas.
We took him to Cabela's and had him draw the Diamond at 15lbs and it was tough, but for the 2nd time ever drawing it, got it pretty easy, so my dad picked this up for him for 40$ I think on sale? Was that a horrible decision?
http://www.basspro.com/Bear-Archery-Brave-Youth-Compound-Bow-Set/product/14091907120614/We almost got the diamond since it can go down to 5lbs or so, but didn't want to drop the extra coin, since I don't bow hunt, yet... just on a passing whim of a 6 year old. Of course if he decides it's for him, I would of course have to get one as well...