I had a young fella come over to Oz from the states to hunt sambar, we dropped into a sports store to buy some heavier loads as my ones were only 150 gr, they had some 200 Gr packets out the back and these we took into the mountains. Upon arrival at our camping spot which was on top of the Ridge...
Nikon cool pixels p900, large sd card and keep taking the pictures, edit as time allows, say at night. Can't take enough pics, took a photo of an aurora Australis last nite, first time on film, quite a buzz.
My 300 wsm shoots 165 gr speer spbt at 3250, no jacking the speed there. 180 gr at 3000. I've never owned a seven mil, but have shot the O'Connor for a few yrs.
60inch long, 50 lb draw but doubt your son will pull 50 lb, or even you, and if you can it's likely to do some damage to your shoulder. As previously said go to an archery shop.
Cheap arrows, you'll break a few to start with. Go to google there's tons of instructional vids, and get your elbow up high, otherwise lots of pain in the shoulder, and a little often is better than a lot all at once.
Welcome to the trad crew