I'd recommend that he try a 300 WM before buying if he's concerned about recoil. If the recoil doesn't bother him, go for it. Just because the caliber is capable at long range doesn't automatically translate into the innate ability of the shooter to do so. The best way to be a successful long-range shooter is practice. If he's afraid of the recoil, practice probably won't happen. He'd be better off with a caliber that won't beat him up that he'll be comfortable shooting.
Lots of hunters hit stuff regularly at long range with 30-06's, 7MM Mag's, .270's, etc.