I haven't seen the Toursaver book yet, but I do like the Northern Lights book. It has coupons for tours/cruises/other tourist type stuff, but also has lots of coupons for restaurants and other things locals might find more useful. So your brother can probably make use of anything you don't use.

One thing though, the coupons for the tours/activites often are good for certain times of year (non-peak.) So if you are arriving at the end of June, it might not have as many coupons that are valid. You can buy it locally, and I'm pretty sure I've seen the Great Alaskan Tour Saver for sale in a gas station or Fred Myers.