For most practical hunting distances a fixed 4 is about all you need.
Most have a nice large front lense which will gather a good amount of light. also you will have a good feild of view.
Most are a pretty inexpensive, but can be a bit hard to find, as it seem 3-9 is the most common.
Another plus is with a fixed 4, he wont be tempted to mess around with it, it really stinks when you have a scope at full power and the deer gets up at your feet, ask me how I know!

also, less moving parts = more durable (quality of scope is of course a factor).
I started with iron sights on my rem 700 .270, then a red dot, then a 3-9. They shoot fast and flat so if you find the point blank range for the load he is using, all he should have to do is put the cross hairs on the deer from X yds to X yds, and make sure he stays within that range.
Good luck
Dave