Yep, .22s, lots of .22s
A few bricks of .22s between now and next hunting season and, with the proper gun and load he will be good to go.
Also commented on was the stock shape of the handi rifle.
Start with the .22s and lots of them, and then get him to shooting a rifle with something other then a club attached.
Lots of nice small rifles out there and as soon as he has used up that 10 bricks of .22s, start him in on a large batch of reduced and light bullet loads in a hunting rifle that fits.
My wife is not a real shoot for the fun of it type person, but I can take her out practicing with her 270, reduced 100gr bullet loads and there is a fair chance she will shoot up everything I take before we leave the range.
They never hurt her, the reduced loads allow for more shooting before the barrel needs to cool down, and the rifle has been shortened to fit her.
My oldest son is a big man, and he was shooting a shot gun barrel on one of the handi rifles and the recoil completely jerked the gun out of his hands on more then one occasion.
And this is a fellow who shoots a 10ga Browning pump out of choice for his water fowl shooting.
There is nothing like a good stock design to help temper recoil.
Keep em coming!
CDOC