I would consider getting him a pair of trail running shoes rather than boots; you might want to consider this for yourself as well. A lot of the folks posting on this forum use nothing else for both on trail travel as well as a lot of off-trail travel. They are generally lighter and much more comfortable than boots and usually don't cost as much either. I use Montrail Hardrocks but New Balance and other running shoe manufacturers have a line of trail runners as well. For me, the only drawback is that your toes get dirty.