The quickest way to get someone into shooting is by not parking them behind something like a 30'06... I suffered a 30'06 for years and finally realized it brought nothing to the table. Kicks the crap out of you for no reason. A lot more fun shooting medium cartridges, especially for deer. My go to gun now is a 6.5×55, and bought my son a 6.5 Creed. Flame away...
This ^^ for exactly the same reasons,,,,
If I were buying today for my two son's, it would be a matching pair of 6.5 CM's.
A 7mm-08 would be my second choice.
The OP says that his son isn't really a gun nut.... he can buy great ammo cheap, for the CM and he'll enjoy shooting it.... my $.02