Henchman Characters work a bit differently. They start off with a slight bit less amount of Stat Points and XP than your character does. Also they only gain XP at half the rate you do (so basically for every 2 XP your character gains they only gain 1 XP). But they can still be incredibly useful, especially if you build them to make up for your character's own shortcomings (like for Leifr for instance giving him some ranged capabilities or perhaps some negotiation or other such things).