I find myself saying this more and more lately:
The longer I hunt whitetails, the more I consider the .243win to be the optimum whitetail deer cartridge.
As for which rifle to get for your boy:
How old is he? If he's a teen, then I'd consider getting a standard sporter weight rifle and then buy a cheap after market stock, cut it down to his current pull and add stock spacers until he fits the standard stock, then put that back on. That way he can use the rifle now, then have the stock grow with him, and keep using his first rifle forever.