[Jack]

The 25-06 is a great choice as an open country deer rifle. Of course, the 270 is, too.
The 25-06 can be almost like 2 different cartridges, in a way. With 100 grain bullets, recoil is little more than the 243 or 6mm Rem- in other words, light. The same 25-06 loaded with 120 grain bullets feels more like a 270 (shooting 130 grain bullets), recoil wise.
If your deer hunting is in wooded areas, you might not need the flat trajectory that are features of both the 25-06 and 270. For woods hunting, a 30-30 or a 257 Roberts (if you can find one) might be just what he needs.
A couple things to keep in mind: light rifles kick more than heavy rifles- often, a lot more. Some of the ultralight rifles on the market that weigh 6 pounds or less can be real nasty to shoot from the bench, with recoil that can be surprisingly heavy.
Often the superlight rifles have short barrels, too- short barrels are LOUD. And muzzle blast is often perceived as recoil.