i second what frizz has said about the 30-06sprg with milder recoiling rounds. my browning medallion chmabered in 30-06sprg has a alot more kick with 150gr' s than my savage 10FCM in 308win using 180gr. bullets.
i like the idea of the 260rem in a model 7 youth rifle. but i would base your options on what you are gonna hunt. maybe a 270win he might find a better choice?