I'd do a hike up to the Kain hut or Applebee campground in the Bugs... If nothing there inspires him to climb a bit of granite, well then, nothing will. And the views just can't be beat anywhere under 6000M.
Ditto that. So inspiring we bought touring bikes years ago just to do the ride from Jasper to Banff. You can exit the area from Jasper going west on the Yellowhead highway and get a roadside view of Robson (wow!) or exit going west on 93 to Radium and go to the hot springs. Lots of options there. Drive to Revelstoke is also way worthwhile for the view of Sir Donald, another wow.
If you go into GLAC and end up at Lake McDonald, do yourself a big favor by driving to the north end of the lake to check out Lake McDonald Ranger Station. It is a rare and precious look WAY back in time.
It's a trip in there.
Almost doesn't feel like you should be allowed to be in there.