Great plan. Teach him to shoot small groups. Breathing, cheek position, trigger discipline. Eye position behind the scope. That will slow him down. Many Savage Model 12 bolt guns in .223 are MOA or sub MOA capable if the ammo is capable and the shooter does his thing.
Handloading and shooting only handloaded ammo is also a way to slow things down. Good handloads can be well under MOA with proper components. I have match component handloads that are sub 1/2 MOA. There is a reloading section here with lots of tips for both beginners and experienced people. Chances are good that even casually developed reloads, if you learn correctly, will be more accurate than most commercial bulk loads you are probably using for blasting.
For example, my M193 equivalent uses ordinary 55 grain Hornady FMJ bullets. They are (or were) cheap and surprisingly good for the price. Loaded in Federal LC cases over a conservative, safe load of just about any appropriate powder, they shoot about 1.1-1.2" groups at 100 yards. Primers are getting scarce right now. I hope you buddy has a lot.
Higher power magnification also slows rate of fire and optimizes group size.
Also, give thought to a target grade .22LR. It's a great trainer for longer range centerfire precision shooting.