I can remember the many arguments I had with my dad when I wanted to lift my first Explorer after I turned 16... fun times!
First off, if you're worried about safety, do you know what lift he is planning on installing? Are you guys planning on installing it at home or are you having a shop do it?
As far as wheels and tires go.. I'd say there are a few factors that play into what you should be looking at.
1. How much off road use is the truck actually going to get?
2. If it is going to see off road use, are we talking gravel/dirt roads or more "wheeling" trails?
3. Even if he is going to be going off road, how much is he going to be driving on road daily/often?
Those questions are best to ask when you're deciding what kind of wheels (if any) to purchase and what kind of tire is going to be most suitable.
Just from my experience, lifting a truck and fitting larger tires and/or wheels is costly and time consuming, but can be very rewarding. Installing a lift on your own can be very frustrating and time consuming, so if that is the route you guys are planning on taking, feel free to ask any questions you guys may have and I'll do my best to point you in the direction of helpful threads and offer what knowledge I have.