I would think long and hard about it. We are all noobs and started with some H&Rs, which are great but have their limits. My kids are small so YMMV but my 10 year old shoots an H&R JR Classic 410 - mostly at stationary targets as its hard to hit clays with a 410. That gun weighs about 6#. Initially the muzzle would start to come down but now he handles it fine. I bought the Jr. Classic in 20 for my tweens but it only weighs 5#! It's the same gun as the 410 but the barrel is bored out more so the gun is much lighter. It hits pretty hard even with Fiocchi light training loads (3/4 oz., 1075 fps via ableammo). As they've grown, I've added weight to the stock (roll of nickels = 7 oz.) and put a 26" barrel but it is still pretty light. I also put a slip-on recoil pad over the standard pad (which is a decent rubber pad) to help cushion the hit and to extend LOP. The gun is just too light for a 20. I have a Topper Deluxe Classic 20 and that gun is 7.25#. That one is quite comfortable but it is a bit heavy for the kids to manage. Personally, if using a break action, I would want at least 6# for a 20. If he can't balance that, I would think about another type or drop down to the 410.
